WAEC SSCE - General Mathematics - 2013 (Objective)

Question 1 Report

Which of the following is not a probability of Mary scoring 85% in a mathematics test?

0.15

0.57

0.94

1.01 Correct answer

Answer Details

The probability of an event happening can never be greater than 1. Therefore, 1.01 cannot be a probability of Mary scoring 85% in a mathematics test.

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Percentages

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Question 2 Report

If 2 log x (3$\frac{3}{8}$) = 6, find the value of x

$\frac{3}{2}$ Correct answer

$\frac{4}{3}$

$\frac{2}{3}$

$\frac{1}{2}$

Answer Details

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Logarithms

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Question 3 Report

In the diagram, O is the centre of the circle. OM||XZ and < ZOM = 25^o

50^o

55^o

60^o Correct answer

65^o

Answer Details

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Sine, Cosine And Tangent Of An Angle

Representation Of Data

Circles

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Question 4 Report

Given that p^{$\frac{1}{3}$} = $\frac{3\sqrt{q}}{r}$, make q the subject of the equation

q = p$\sqrt{r}$

q = p³r

q = pr³

q = pr^{$\frac{1}{3}$} Correct answer

Answer Details

We want to solve for q, so we need to isolate it on one side of the equation. First, we can isolate the cube root of p by cubing both sides of the equation: p^(1/3) = (3√q)/r (p^(1/3))³ = (3√q)³/r³ p = (27q)/r³ Next, we can isolate q by multiplying both sides by r³/27: (p/27)r³ = q Therefore, the solution is q = (p/27)r³, which is equivalent to q = pr^(1/3).

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Number Bases

Quadratic Equations

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Question 5 Report

If y varies directly s the square root of (x + 1) and y = 6 when x = 3, find x when y = 9

8 Correct answer

Answer Details

We are given that y varies directly with the square root of (x+1), which can be written as y=k√(x+1), where k is the constant of variation. To find k, we use the given values of x and y: y=k√(x+1) 6=k√(3+1) 6=k√4 6=2k k=3 So the equation for y in terms of x is y=3√(x+1). To find x when y=9, we substitute these values into the equation and solve for x: 9=3√(x+1) 3=√(x+1) 9=x+1 x=8 Therefore, x = 8 when y = 9.

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Variation

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Question 6 Report

In what number base is the addition 465 + 24 + 225 = 1050?

ten

nine

eight

seven Correct answer

Answer Details

To solve this problem, we need to find out in what base the addition statement is true. Let's assume the base is "b". Then, in the units column, we have: - 5 + 4 = 10, so we write down 0 and carry-over 1. - In the "b" column, we have: 6 + 2 + 2 + 1 = 11, so we write down 1 and carry-over 1. - In the "b^2" column, we have: 4 + 2 + 5 + 1 = 12, so we write down 2 and carry-over 1. - In the "b^3" column, we have: 4 + 2 + 2 = 8. Putting these digits together, we get the number 8201 in base "b". Now, we need to check if this number is equal to 1050 in base 10. 8201 in base "b" means: 8 x b^3 + 2 x b^2 + 0 x b + 1 x 1 = 1050 Rearranging the terms, we get: 8 b^3 + 2 b^2 + 1 = 1050 Subtracting 1 from both sides: 8 b^3 + 2 b^2 = 1049 Since b is a positive integer, we can see that b must be greater than 5. Trying b = 6, we get: 8 x 6^3 + 2 x 6^2 = 1048 This is not equal to 1049, so we need to try a larger base. Trying b = 7, we get: 8 x 7^3 + 2 x 7^2 = 1049 This is equal to 1049, so the base is 7. Therefore, the answer is seven.

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Number Bases

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Question 7 Report

The graph of the relation y = x2 + 2x + k passes through the point (2, 0). Find the values of k

zero

-2

-4

-8 Correct answer

Answer Details

We are given the equation y = x2 + 2x + k and we know that it passes through the point (2,0). We can substitute x = 2 and y = 0 into the equation to find k. Substituting, we get: 0 = 22 + 2(2) + k 0 = 4 + 4 + k 0 = 8 + k k = -8 Therefore, the value of k is -8, which is the fourth option.

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Quadratic Equations

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Question 8 Report

The pie chart shows the distribution of 600 mathematics textbooks for Arts, Business, Science and Technical Classes. How many textbooks are for the technical class?

100

150

200

250 Correct answer

Answer Details

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Mensuration

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Question 9 Report

Four oranges sell for Nx and three mangoes sell for Ny. Olu bought 24 oranges and 12 mangoes. How much did he pay in terms of x and y?

N94x + 6y)

N(6x + 4y) Correct answer

N(24x + 12y)

N(12x + 24y)

Answer Details

Four oranges sell for Nx, so one orange costs $\frac{N}{4}x$. Three mangoes sell for Ny, so one mango costs $\frac{N}{3}y$. Olu bought 24 oranges and 12 mangoes, so he paid: \[24 \cdot \frac{N}{4}x + 12 \cdot \frac{N}{3}y = 6Nx + 4Ny\] Therefore, Olu paid N(6x + 4y) in terms of x and y. The answer is option (B).

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Matrices And Determinants

Modular Arithmetic

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Question 10 Report

In the diagram, PQ is a straight line. Calculate the value of the angle labelled 2y

130^o

120^o

110^o

100^o Correct answer

Answer Details

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Angles

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Question 11 Report

Simplify: $\frac{x^2 - y^2}{(x + y)^2} + \frac{(x - y)^2}{(3x + 3y)}$

$\frac{x - y}{3}$

x + y

$\frac{3}{x - y}$ Correct answer

x - y

Answer Details

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Solution Of Linear Equations

Algebraic Expressions

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Question 12 Report

A pyramid has a rectangular base with dimensions 12m by 8m. If its height is 14m, calculate the volume

322m³

448m³ Correct answer

632m²

840m²

Answer Details

The formula for the volume of a pyramid is given by V = 1/3 * B * h, where B is the area of the base and h is the height of the pyramid. In this case, the base of the pyramid is a rectangle with dimensions 12m by 8m, so its area is A = 12m * 8m = 96m². The height of the pyramid is given as 14m. Substituting these values into the formula, we have V = 1/3 * 96m² * 14m = 448m³. Therefore, the volume of the pyramid is 448m³.

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Volumes

Angles

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Question 13 Report

A cube and cuboid have the same base area. The volume of the cube is 64cm$^3$ while that of the cuboid is 80cm$^3$. Find the height of the cuboid

1cm

3cm

5cm Correct answer

6cm

Answer Details

Let the base area of the cube be x, then the length of one side of the cube is $\sqrt[3]{64}$ = 4 cm. Since the base area of the cube and cuboid are equal, the base of the cuboid must also have an area of x. The volume of the cuboid is given as 80cm$^3$ which can be expressed as: 80 = x × h, where h is the height of the cuboid We know that the length of the base of the cuboid is equal to the length of the side of the cube. Therefore, the dimensions of the cuboid are 4 cm by 4 cm by h cm. Using the formula for the volume of a cuboid, we get: Volume of cuboid = length × width × height = 4 × 4 × h = 16h Substituting 80 for the volume of the cuboid, we get: 16h = 80 Solving for h, we get: h = 5cm Therefore, the height of the cuboid is 5cm. Hence, the correct answer is 5cm.

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Question 14 Report

Using the histogram, estimate the mode of distribution

51.5

52.5

53.5 Correct answer

54.5

Answer Details

In a histogram, the mode is the value with the highest frequency, or the tallest bar. Looking at the given histogram, it appears that the tallest bar is the one corresponding to the interval between 52 and 54, which means that the mode lies somewhere in that interval. Since the interval width is 2, we can estimate the mode to be around the middle of the interval, which is (52 + 54)/2 = 53. Therefore, the estimated mode of the distribution is 53.5. So, the answer is (c) 53.5.

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Representation Of Data

Measures Of Location

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Question 15 Report

A chord is 2cm from the centre of a circle. If the radius of the circle is 5cm, find the length of the chord

2$\sqrt{21}$cm Correct answer

$\sqrt{42}$cm

2$\sqrt{19}$cm

$\sqrt{21}$cm

Answer Details

To solve this problem, we can use the Pythagorean theorem to find the length of the chord. We know that the radius of the circle is 5cm and the distance from the centre of the circle to the chord is 2cm. We can draw a perpendicular line from the centre of the circle to the chord, which will divide the chord into two equal parts. This perpendicular line will also bisect the chord and form a right triangle with the radius of the circle and half of the chord. The hypotenuse of this triangle is the radius of the circle, which is 5cm, and one leg is half of the chord, which we can call x. The other leg is the distance from the centre of the circle to the chord, which is 2cm. Using the Pythagorean theorem, we can solve for x: 5^2 = x^2 + 2^2 25 = x^2 + 4 x^2 = 21 x = √21 Therefore, the length of the chord is twice the value of x, which is 2√21cm. Hence, the correct answer is option A.

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Question 16 Report

Given that P = x² + 4x - 2, Q = 2x - 1 and Q - p = 2, find x

-2

-1 Correct answer

Answer Details

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Algebraic Expressions

Quadratic Equations

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Question 17 Report

If Un = n(n² + 1), evaluate U5 - U4

62 Correct answer

Answer Details

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Sequence And Series

Financial Arithmetic

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Question 18 Report

The pie chart shows the distribution of 600 mathematics textbooks for Arts, Business, Science and Technical Classes. What percentage of the total number of textbooks belongs to science?

12$\frac{1}{2}$% Correct answer

$\frac{205}{6}$%

25%

$\frac{412}{3}$%

Answer Details

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Question 19 Report

Using the histogram, what is the median class?

60.5 - 70.5

50.5 - 60.5

40.5 - 50.5 Correct answer

30.5 - 40.5

Answer Details

To find the median class in a histogram, we need to identify the class interval that contains the median value. The median is the middle value in a dataset, so we need to find the midpoint of the data. To find the median class: 1. Add up the frequencies in the histogram starting from the left-hand side until the total is greater than or equal to the total number of data points divided by 2. 2. The median class is the class interval that contains the midpoint of the data. In this histogram, the total number of data points is 80. The midpoint is (80 + 1)/2 = 40.5. Starting from the left-hand side, we can add up the frequencies: 8 + 19 + 24 = 51. The median falls within the interval 40.5 - 50.5, which is the third interval. Therefore, the median class is 40.5 - 50.5.

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Representation Of Data

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Question 20 Report

Given that (x + 2)(x² - 3x + 2) + 2(x + 2)(x - 1) = (x + 2) M, find M

(x + 2)²

x(x + 2)

xv + 2

x² - x Correct answer

Answer Details

We can begin by factoring out (x + 2) from both terms on the left side of the equation: (x + 2)(x² - 3x + 2) + 2(x + 2)(x - 1) = (x + 2) M (x + 2)[(x² - 3x + 2) + 2(x - 1)] = (x + 2) M Simplifying the expression in the brackets, we get: (x + 2)(x² - x) = (x + 2) M Now, we can cancel out (x + 2) from both sides of the equation: x² - x = M Therefore, the value of M is simply x² - x.

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Solution Of Linear Equations

Algebraic Expressions

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Question 21 Report

Express $\frac{2}{x + 3} - \frac{1}{x - 2}$ as a simple fraction

$\frac{x - 7}{x^2 + x - 6}$ Correct answer

$\frac{x - 1}{x^2 + x - 6}$

$\frac{x - 2}{x^2 + x - 6}$

$\frac{x - 27}{x^2 + x - 6}$

Answer Details

To add fractions, we need to have a common denominator. In this case, the common denominator is $(x+3)(x-2)$. Therefore, we need to convert each fraction to have this denominator. \[\frac{2}{x+3} - \frac{1}{x-2} = \frac{2(x-2)}{(x+3)(x-2)} - \frac{(x+3)}{(x+3)(x-2)}\] Simplifying the above expression, we have: \[\frac{2(x-2) - (x+3)}{(x+3)(x-2)} = \frac{2x - 4 - x - 3}{(x+3)(x-2)} = \frac{x-7}{(x+3)(x-2)}\] Therefore, $\frac{2}{x + 3} - \frac{1}{x - 2} = \boxed{\frac{x-7}{(x+3)(x-2)}}$. The correct option is (a).

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Algebraic Fractions

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Question 22 Report

Find the value of m in the diagram

34^o

27^o

23^o

17^o Correct answer

Answer Details

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Angles

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Question 23 Report

The bearing of Y from X is 060^o and the bearing of Z from Y = 060^o. Find the bearing of X from Z

300^o

240^o Correct answer

180^o

120^o

Answer Details

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Bearings

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Question 24 Report

In the diagram, PQRST is a regular polygon with sides QR and TS produced to meet at V. Find the size of < RVS

36^o Correct answer

54^o

60^o

72^o

Answer Details

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Triangles And Polygons

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Question 25 Report

Simplify $\frac{1\frac{7}{8} \times 2\frac{2}{5}}{6\frac{3}{4} \div \frac{3}{4}}$

4$\frac{1}{2}$

$\frac{1}{2}$ Correct answer

Answer Details

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Fractions, Decimals And Approximations

Surds (radicals)

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Question 26 Report

What is the locus of the point X which moves relative to two fixed points P and M on a plane such that < PXM = 30^o

thebisector of the straight line joining P and M

an arc of a circle with PM as a chord Correct answer

the bisector of angle PXM

a circle centre X and radius PM

Answer Details

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Loci

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Question 27 Report

An object is 6m away from the base of a mast. The angle of depression of the object from the top pf the mast is 50^o, Find, correct to 2 decimal places, the height of the mast

8.60m

7.51m

7.15m Correct answer

1.19m

Answer Details

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Bearings

Angles Of Elevation And Depression

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Question 28 Report

The slant height of a cone is 5cm and the radius of its base is 3cm. Find, correct to the nearest whole number, the volume of the cone. ( Take $\pi = \frac{22}{7}$)

48cm³

47cm³

38cm³ Correct answer

12cm³

Answer Details

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Volumes

Integration

Inequalities

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Question 29 Report

If $\frac{1}{2}$x + 2y = 3 and $\frac{3}{2}$x and $\frac{3}{2}$x - 2y = 1, find (x + y)

3 Correct answer

Answer Details

Given the equations: \begin{align*} \frac{1}{2}x + 2y &= 3 \\ \frac{3}{2}x - 2y &= 1 \\ \end{align*} We can solve for x and y using simultaneous equations: First, multiply the first equation by 2: \begin{align*} x + 4y &= 6 \\ \frac{3}{2}x - 2y &= 1 \\ \end{align*} Then, multiply the second equation by 2: \begin{align*} x + 4y &= 6 \\ 3x - 4y &= 2 \\ \end{align*} Add the equations together: \begin{align*} 4x &= 8 \\ x &= 2 \\ \end{align*} Substitute x = 2 back into the first equation: \begin{align*} \frac{1}{2}(2) + 2y &= 3 \\ 1 + 2y &= 3 \\ 2y &= 2 \\ y &= 1 \\ \end{align*} Finally, substitute x = 2 and y = 1 into (x + y): \begin{align*} x + y &= 2 + 1 \\ &= 3 \\ \end{align*} Therefore, (x + y) = 3, and the answer is.

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Solution Of Linear Equations

Algebraic Expressions

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Question 30 Report

in the diagram, the height of a flagpole |TF| and the length of its shadow |FL| re in the ratio 6:8. Using k as a constant of proportionality, find the shortest distance between T and L

7K units

10K units Correct answer

12K units

14k units

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Indices

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Question 31 Report

An open cone with base radius 28cm and perpendicular height 96cm was stretched to form sector of a circle. calculate the arc of the sector (Take $\pi = \frac{22}{7}$)

8800cm² Correct answer

8448cm²

4400cm²

4224cm²

Answer Details

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Algebraic Expressions

Statistics

Progression

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Question 32 Report

In the diagrams, |XZ| = |MN|, |ZY| = |MO| and |XY| = |NO|. Which of the following statements is true?

$\bigtriangleup$ ZYX = $\bigtriangleup$ OMN

$\bigtriangleup$ YZX = $\bigtriangleup$ NOM

$\bigtriangleup$ ZXY= $\bigtriangleup$ MON

$\bigtriangleup$ XYZ= $\bigtriangleup$ NOM Correct answer

Answer Details

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Triangles And Polygons

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Question 33 Report

Find the values of k in the equation 6k² = 5k + 6

{$\frac{-2}{3}, \frac{-3}{2}$}

{$\frac{-2}{3}, \frac{3}{2}$} Correct answer

{$\frac{2}{3}, \frac{-3}{2}$}

{$\frac{2}{3}, \frac{3}{2}$}

Answer Details

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Quadratic Equations

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Question 34 Report

When a number is subtracted from 2, the result equals 4 less than one-fifth of the number. Find the number

$\frac{15}{2}$

5 Correct answer

$\frac{5}{2}$

Answer Details

Let's call the number we are looking for "x". According to the problem, when we subtract x from 2, the result is equal to 4 less than one-fifth of the number. In mathematical terms, this can be written as: 2 - x = (1/5)x - 4 To solve for x, we can start by simplifying the equation by adding x to both sides: 2 = (6/5)x - 4 Next, we can add 4 to both sides: 6 = (6/5)x Finally, we can multiply both sides by 5/6 to isolate x: x = 5 Therefore, the answer is 5.

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Solution Of Linear Equations

Quadratic Equations

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Question 35 Report

Using the venn diagram, find n(x $\cap$ y¹)

2 Correct answer

Answer Details

The intersection of two sets x and y1 is represented by the overlapping region of the two circles. From the diagram, we can see that the number of elements in the intersection is 2. Therefore, n(x $\cap$ y1) = 2.

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Sets

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Question 36 Report

The distance between two towns is 50km. It is represented on a map by 5cm. Find the scale used

1: 1,000,000 Correct answer

1: 500,000

1: 100,000

1: 10,000

Answer Details

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Number Bases

Areas

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Question 37 Report

If sin x = $\frac{5}{13}$ and 0^o $\leq$ x $\leq$ 90^o, find the value of (cos x - tan x)

$\frac{7}{13}$

$\frac{12}{13}$

$\frac{79}{156}$ Correct answer

$\frac{209}{156}$

Answer Details

We know that sin x = $\frac{5}{13}$ and 0^o $\leq$ x $\leq$ 90^o. First, we can find the value of cos x using the identity: sin² x + cos² x = 1 sin² x + cos² x = 1 $\frac{25}{169}$ + cos² x = 1 cos² x = $\frac{144}{169}$ cos x = $\pm$$\frac{12}{13}$ Since 0^o $\leq$ x $\leq$ 90^o, we know that cos x is positive. Therefore, cos x = $\frac{12}{13}$. Next, we can find the value of tan x using the identity: tan x = $\frac{sin x}{cos x}$ tan x = $\frac{sin x}{cos x}$ = $\frac{\frac{5}{13}}{\frac{12}{13}}$ = $\frac{5}{12}$ Finally, we can find the value of (cos x - tan x) as: cos x - tan x = $\frac{12}{13}$ - $\frac{5}{12}$ = $\frac{79}{156}$ Therefore, the answer is (cos x - tan x) = $\frac{79}{156}$.

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Sine, Cosine And Tangent Of An Angle

Fractions, Decimals, Approximations And Percentage

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Question 38 Report

If $\sqrt{50} - K\sqrt{8} = \frac{2}{\sqrt{2}}$, find K

-2

-1

2 Correct answer

Answer Details

We can start by simplifying the left-hand side of the equation using the laws of square roots: \begin{align*} \sqrt{50} - K\sqrt{8} &= \sqrt{25\cdot 2} - K\sqrt{4\cdot 2} \\ &= 5\sqrt{2} - 2K\sqrt{2} \\ &= \sqrt{2}(5 - 2K). \end{align*} Now, we can rewrite the given equation as: \begin{align*} \sqrt{2}(5 - 2K) &= \frac{2}{\sqrt{2}} \\ 5 - 2K &= \frac{2}{\sqrt{2}} \cdot \frac{1}{\sqrt{2}} \\ 5 - 2K &= \frac{2}{2} \\ 5 - 2K &= 1 \\ -2K &= -4 \\ K &= 2. \end{align*} Therefore, the value of K that satisfies the equation is 2.

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Surds (radicals)

Lengths And Perimeters

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Question 39 Report

In the diagram, PQRS is a rhombus and < PSQ = 35^o. Calculate the size of < PRO

65^o

55^o

45^o

35^o Correct answer

Answer Details

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Euclidean Geometry

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Question 40 Report

If x = 64 and y = 27, evaluate: $\frac{x^{\frac{1}{2}} - y^{\frac{1}{3}}}{y - x^{\frac{2}{3}}}$

2$\frac{1}{5}$

$\frac{5}{11}$ Correct answer

$\frac{11}{43}$

Answer Details

We can start by substituting the given values: \begin{align*} \frac{x^{\frac{1}{2}} - y^{\frac{1}{3}}}{y - x^{\frac{2}{3}}} &= \frac{64^{\frac{1}{2}} - 27^{\frac{1}{3}}}{27 - 64^{\frac{2}{3}}} \\ &= \frac{8 - 3}{27 - 16} \\ &= \frac{5}{11} \end{align*} Therefore, the answer is $\frac{5}{11}$.

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Number Bases

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Question 41 Report

In the diagram, PRST is a square. If |PQ| = 24cm. |QR| = 10cm and < PQR = 90^o, find the perimeter of the polygon PQRST.

112cm Correct answer

98cm

86cm

84cm

Answer Details

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Question 42 Report

A sales boy gave a change of N68 instead of N72. Calculate his percentage error

5$\frac{5}{9}$% Correct answer

5$\frac{15}{17}$%

Answer Details

The sales boy gave a change of N68 instead of N72, which means he gave N4 less than he should have. To find the percentage error, we use the formula: Percentage Error = (Error / True Value) × 100% In this case, the True Value is N72 and the Error is N4. Substituting these values into the formula, we get: Percentage Error = (4 / 72) × 100% Percentage Error = 0.055555... × 100% Percentage Error = 5.5555...% Rounding off to the nearest whole number, we get: Percentage Error ≈ 6% Therefore, the sales boy's percentage error is approximately 6%. The closest option to this answer is 5$\frac{5}{9}$%, so the answer would be: - 5$\frac{5}{9}$%

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Modular Arithmetic

Financial Arithmetic

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Question 43 Report

Multiply 2.7 x 10^-4 by 6.3 x 10⁶ and leave your answers in standard form

1.7 x 10³

1.70 x 10³

1.701 x 10³ Correct answer

17.01 x 10³

Answer Details

To multiply two numbers in scientific notation, we simply multiply their coefficients and add their exponents. (2.7 x 10^-4) x (6.3 x 10⁶) = (2.7 x 6.3) x 10^-4+6 = 17.01 x 10² We can express 17.01 x 10² in standard form by moving the decimal point to the left two places, which gives us: 1.701 x 10³ Therefore, the correct answer is (c) 1.701 x 10³.

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Number Bases

Lengths And Perimeters

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Question 44 Report

An interior angle of a regular polygon is 5 times each exterior angle. How many sides has the polygon?

12 Correct answer

Answer Details

In a regular polygon, each exterior angle is equal to 360 degrees divided by the number of sides. Let the number of sides be represented by n. Therefore, the measure of each exterior angle is 360/n. Since the interior angle and exterior angle are supplementary, we can write: Interior angle + Exterior angle = 180 degrees Let x be the measure of each interior angle. We are given that each interior angle is 5 times each exterior angle, so: x = 5(360/n - x) Simplifying and solving for x, we get: x = 150 degrees The sum of the interior angles of an n-sided polygon is (n - 2) × 180 degrees. Since each interior angle in our polygon is 150 degrees, we can write: n × 150 = (n - 2) × 180 Simplifying and solving for n, we get: n = 12 Therefore, the polygon has 12 sides. So, the correct answer is 12.

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Triangles And Polygons

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Question 45 Report

If p = (y : 2y $\geq$ 6) and Q = (y : y -3 $\geq$ 4), where y is an integer, find p$\cap$Q

{3, 4}

{3, 7}

{3, 4, 5, 6, 7} Correct answer

{4, 5, 6}

Answer Details

The set p represents all values of y such that 2y is greater than or equal to 6. Simplifying the inequality 2y $\geq$ 6 gives y $\geq$ 3. Therefore, p can be written as p = {y: y $\geq$ 3}. Similarly, the set Q represents all values of y such that y - 3 is greater than or equal to 4. Simplifying the inequality y - 3 $\geq$ 4 gives y $\geq$ 7. Therefore, Q can be written as Q = {y: y $\geq$ 7}. The intersection of p and Q, denoted by p$\cap$Q, is the set of all values of y that are in both p and Q. Since p contains all values of y greater than or equal to 3 and Q contains all values of y greater than or equal to 7, the intersection of p and Q is {y: y $\geq$ 7}. Therefore, p$\cap$Q = {7, 8, 9, 10, ...}. The correct option is (c) {3, 4, 5, 6, 7}.

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Question 46 Report

In the diagram, ST//PQ reflex angle SRQ = 198^o and < RQp = 72^o. Find the value of y

18^o

54^o Correct answer

87^o

92^o

Answer Details