Year : 
2016
Title : 
Mathematics (Core)
Exam : 
WASSCE/WAEC MAY/JUNE

Paper 1 | Objectives

11 - 20 of 49 Questions

# Question Ans
11.

Given that 2x + y = 7 and 3x - 2y = 3, by how much is 7x greater than 10?

A. 1

B. 3

C. 7

D. 17

Detailed Solution

2x + y = 7...(1)

3x - 2y = 3...(2)

From (1), y = 7 - 2x for y in (2)

3x - 2(7 - 2x) = 3

3x - 14 + 4x = 3

7x + 3 + 14 = 17

x = \(\frac{17}{7}\)

Hence, 7 x \(\frac{17}{7}\)

= 17 - 10

= 7
12.

Simplify; \(\frac{2}{1 - x} - \frac{1}{x}\)

A. \(\frac{x + 1}{x(1 - x)}\)

B. \(\frac{3x - 1}{ x(1 - x)}\)

C. \(\frac{3x + 1}{ x(1 - x)}\)

D. \(\frac{x + 1}{ x(1 - x)}\)

Detailed Solution

\(\frac{2}{1 - x} - \frac{1}{x}\) = \(\frac{2x - 1(1 - x)}{x(1 - x)}\)

= \(\frac{2x - 1(1 + x)}{x(1 - x)}\)

= \(\frac{3x - 1}{x(1 - x)}\)
13.

Make s the subject of the relation: P = S + \(\frac{sm^2}{nr}\)

A. s = \(\frac{mrp}{nr + m^2}\)

B. s = \(\frac{nr + m^2}{mrp}\)

C. s = \(\frac{nrp}{mr + m^2}\)

D. s = \(\frac{nrp}{nr + m^2}\)

Detailed Solution

P = S + \(\frac{sm^2}{nr}\)

P = S(1 + \(\frac{m^2}{nr}\))

P = S(1 + \(\frac{nr + m^2}{nr}\))

nrp = S(nr + m2)

S = \(\frac{nrp}{nr + m^2}\)
14.

Factorize; (2x + 3y)2 - (x - 4y)2

A. (3x - y)(x + 7y)

B. (3x + y)(2x - 7y)

C. (3x + y)(x - 7y)

D. (3x - y)(2x + 7y)

Detailed Solution

(2x + 3y)2 - (x - 4y)2

= (2x + 3y)(2x + 3y) - (x - 4y)(x - 4y)

= 4x2 + 12xy + 9y2 - (x2 - 8xy+ 16y2)

= 4x2 + 12xy + 19y2 - x2 + 8xy - 16y2

= 3x2 + 20xy - 7y2

= 3x2 + 21xy - xy - 7y2

= 3x(x + 7y) - y(x + 7y)

= (3x - y)(x + 7y)
15.

The curve surface area of a cylinder, 5cm high is 110cm 2. Find the radius of its base. [Take \(\pi = \frac{22}{7}\)]

A. 2.6cm

B. 3.5cm

C. 3.6cm

D. 7.0cm

Detailed Solution

Curved surface area of cylinder = 2\(\pi\)rh

110 = 2 x \(\frac{22}{7}\) x r x 5

r = \(\frac{110 \times 7}{44 \times 5}\)

= 3.5cm
16.

The volume of a pyramid with height 15cm is 90cm3. If its base is a rectangle with dimension xcm by 6cm, find the value of x

A. 3

B. 5

C. 6

D. 8

Detailed Solution

Volume of pyramid = \(\frac{1}{3}\)lbh

90 = \(\frac{1}{3} \times x \times 6 \times 15\)

x = \(\frac{90 \times 33}{6 \times 15}\)

= 3
17.

A straight line passes through the points P(1,2) and Q(5,8). Calculate the gradient of the line PQ

A. \(\frac{3}{5}\)

B. \(\frac{2}{3}\)

C. \(\frac{3}{2}\)

D. \(\frac{5}{3}\)

Detailed Solution

Let: (x1, y1) = (1, 2)

(x2, y2) = (5, 8)

The gradient m of \(\bar{PQ}\) is given by

m = \(\frac{y_2 y_1}{x_2 - x_1}\)

= \(\frac{8 - 2}{5 - 1}\)

= \(\frac{6}{4}\)

= \(\frac{3}{2}\)
18.

A straight line passes through the point P(1,2) and Q
(5,8). Calculate the length PQ

A. \(4\sqrt{11}\)

B. \(4\sqrt{10}\)

C. \(2\sqrt{17}\)

D. \(2\sqrt{13}\)

Detailed Solution

|PQ| = \(\sqrt{(x_2 - X- 1) + (y_2 - y_1)^2}\)

= \(\sqrt{(5 - 1)^2 + (8 - 2)^2}\)

= \(\sqrt{4^2 + 6^2}\)

= \(\sqrt{16 + 36}\)

= \(\sqrt{52}\)

= 2\(\sqrt{13}\)
19.

If cos \(\theta\) = x and sin 60o = x + 0.5 0o < \(\theta\) < 90o, find, correct to the nearest degree, the value of \(\theta\)

A. 32o

B. 40o

C. 60o

D. 69o

Detailed Solution

sin 60o = x + 0.5 0o(given)

0.8660 = x + 0.5

0.8660 - 0.5 = x

x = 0.3660

cos\(\theta\) = x(given)

cos\(\theta\) = 0.3660

Hence, \(\theta\) = cos-1(0.3660)

= 68.53o

= 69o (nearest degree)
20.

\(\begin{array}{c|c}
Age(years) & 13 & 14 & 15 & 16 & 17 \\
\hline
Frequency & 10 & 24 & 8 & 5 & 3
\end{array}\)

The table shows the ages of students in a club. How many students are in the club?

A. 50

B. 55

C. 60

D. 65

Detailed Solution

Number of students in the club is

10 + 24 + 8 + 5 + 3 = 50
11.

Given that 2x + y = 7 and 3x - 2y = 3, by how much is 7x greater than 10?

A. 1

B. 3

C. 7

D. 17

Detailed Solution

2x + y = 7...(1)

3x - 2y = 3...(2)

From (1), y = 7 - 2x for y in (2)

3x - 2(7 - 2x) = 3

3x - 14 + 4x = 3

7x + 3 + 14 = 17

x = \(\frac{17}{7}\)

Hence, 7 x \(\frac{17}{7}\)

= 17 - 10

= 7
12.

Simplify; \(\frac{2}{1 - x} - \frac{1}{x}\)

A. \(\frac{x + 1}{x(1 - x)}\)

B. \(\frac{3x - 1}{ x(1 - x)}\)

C. \(\frac{3x + 1}{ x(1 - x)}\)

D. \(\frac{x + 1}{ x(1 - x)}\)

Detailed Solution

\(\frac{2}{1 - x} - \frac{1}{x}\) = \(\frac{2x - 1(1 - x)}{x(1 - x)}\)

= \(\frac{2x - 1(1 + x)}{x(1 - x)}\)

= \(\frac{3x - 1}{x(1 - x)}\)
13.

Make s the subject of the relation: P = S + \(\frac{sm^2}{nr}\)

A. s = \(\frac{mrp}{nr + m^2}\)

B. s = \(\frac{nr + m^2}{mrp}\)

C. s = \(\frac{nrp}{mr + m^2}\)

D. s = \(\frac{nrp}{nr + m^2}\)

Detailed Solution

P = S + \(\frac{sm^2}{nr}\)

P = S(1 + \(\frac{m^2}{nr}\))

P = S(1 + \(\frac{nr + m^2}{nr}\))

nrp = S(nr + m2)

S = \(\frac{nrp}{nr + m^2}\)
14.

Factorize; (2x + 3y)2 - (x - 4y)2

A. (3x - y)(x + 7y)

B. (3x + y)(2x - 7y)

C. (3x + y)(x - 7y)

D. (3x - y)(2x + 7y)

Detailed Solution

(2x + 3y)2 - (x - 4y)2

= (2x + 3y)(2x + 3y) - (x - 4y)(x - 4y)

= 4x2 + 12xy + 9y2 - (x2 - 8xy+ 16y2)

= 4x2 + 12xy + 19y2 - x2 + 8xy - 16y2

= 3x2 + 20xy - 7y2

= 3x2 + 21xy - xy - 7y2

= 3x(x + 7y) - y(x + 7y)

= (3x - y)(x + 7y)
15.

The curve surface area of a cylinder, 5cm high is 110cm 2. Find the radius of its base. [Take \(\pi = \frac{22}{7}\)]

A. 2.6cm

B. 3.5cm

C. 3.6cm

D. 7.0cm

Detailed Solution

Curved surface area of cylinder = 2\(\pi\)rh

110 = 2 x \(\frac{22}{7}\) x r x 5

r = \(\frac{110 \times 7}{44 \times 5}\)

= 3.5cm
16.

The volume of a pyramid with height 15cm is 90cm3. If its base is a rectangle with dimension xcm by 6cm, find the value of x

A. 3

B. 5

C. 6

D. 8

Detailed Solution

Volume of pyramid = \(\frac{1}{3}\)lbh

90 = \(\frac{1}{3} \times x \times 6 \times 15\)

x = \(\frac{90 \times 33}{6 \times 15}\)

= 3
17.

A straight line passes through the points P(1,2) and Q(5,8). Calculate the gradient of the line PQ

A. \(\frac{3}{5}\)

B. \(\frac{2}{3}\)

C. \(\frac{3}{2}\)

D. \(\frac{5}{3}\)

Detailed Solution

Let: (x1, y1) = (1, 2)

(x2, y2) = (5, 8)

The gradient m of \(\bar{PQ}\) is given by

m = \(\frac{y_2 y_1}{x_2 - x_1}\)

= \(\frac{8 - 2}{5 - 1}\)

= \(\frac{6}{4}\)

= \(\frac{3}{2}\)
18.

A straight line passes through the point P(1,2) and Q
(5,8). Calculate the length PQ

A. \(4\sqrt{11}\)

B. \(4\sqrt{10}\)

C. \(2\sqrt{17}\)

D. \(2\sqrt{13}\)

Detailed Solution

|PQ| = \(\sqrt{(x_2 - X- 1) + (y_2 - y_1)^2}\)

= \(\sqrt{(5 - 1)^2 + (8 - 2)^2}\)

= \(\sqrt{4^2 + 6^2}\)

= \(\sqrt{16 + 36}\)

= \(\sqrt{52}\)

= 2\(\sqrt{13}\)
19.

If cos \(\theta\) = x and sin 60o = x + 0.5 0o < \(\theta\) < 90o, find, correct to the nearest degree, the value of \(\theta\)

A. 32o

B. 40o

C. 60o

D. 69o

Detailed Solution

sin 60o = x + 0.5 0o(given)

0.8660 = x + 0.5

0.8660 - 0.5 = x

x = 0.3660

cos\(\theta\) = x(given)

cos\(\theta\) = 0.3660

Hence, \(\theta\) = cos-1(0.3660)

= 68.53o

= 69o (nearest degree)
20.

\(\begin{array}{c|c}
Age(years) & 13 & 14 & 15 & 16 & 17 \\
\hline
Frequency & 10 & 24 & 8 & 5 & 3
\end{array}\)

The table shows the ages of students in a club. How many students are in the club?

A. 50

B. 55

C. 60

D. 65

Detailed Solution

Number of students in the club is

10 + 24 + 8 + 5 + 3 = 50