Year : 
2019
Title : 
Mathematics (Core)
Exam : 
WASSCE/WAEC MAY/JUNE

Paper 1 | Objectives

11 - 20 of 50 Questions

# Question Ans
11.

If m : n = 2 : 1, evaluate \(\frac{3m^2 - 2n^2}{m^2 + mn}\)

A. \(\frac{4}{3}\)

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

C. \(\frac{3}{4}\)

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

Detailed Solution

m = 2, n = 1
\(\frac{3m^2 - 2n^2}{m^2 _ mn}\)
= \(\frac{3(2)^2 - 2(1)^2}{2^2 + 2(1)}\)
= \(\frac{12 - 2}{4 + 2} = \frac{10}{6}\)
= \(\frac{5}{3}\)
12.

H varies directly as p and inversely as the square of y. If H = 1, p = 8 and y = 2, find H in terms of p and y.

A. H = \(\frac{p}{4y^2}\)

B. H = \(\frac{2p}{y^2}\)

C. H = \(\frac{p}{2y^2}\)

D. H = \(\frac{p}{y^2}\)

Detailed Solution

H \(\propto\) \(\frac{p}{y^2}\)
H = \(\frac{pk}{y^2}\)
1 = \(\frac{8k}{2^2}\)
k = \(\frac{4}{8}\)
= \(\frac{1}{2}\)
H = \(\frac{p}{2y^2}\)
13.

Solve 4x^{2}\) - 16x + 15 = 0.

A. x = 1\(\frac{1}{2}\) or x = -2\(\frac{1}{2}\)

B. x = 1\(\frac{1}{2}\) or x = 2\(\frac{1}{2}\)

C. x = 1\(\frac{1}{2}\) or x = -1\(\frac{1}{2}\)

D. x = -1\(\frac{1}{2}\) or x -2\(\frac{1}{2}\)

Detailed Solution

4x\(^2\) - 16x + 15 = 0
(2x - 3)(2x - 5) = 0
x = 1\(\frac{1}{2}\) or x = 2\(\frac{1}{2}\)
14.

Simplify: \(\log_{10}\) 6 - 3 log\(_{10}\) 3 + \(\frac{2}{3} \log_{10} 27\)

A. 3 \(\log_{10}^2\)

B. \(\log_{10}^2\)

C. \(\log_{10}^3\)

D. 2 \(\log_{10}^3\)

Detailed Solution

log\(_{10}\) 6 - log\(_{10}\)3\(^3\) + log\(_{10}\) (\(\sqrt[3]{27}\))\(^2\)
= log \(_{10}\) 6 - log \(_{10}\) 27 + log\(_{10}\) 9
= log\(_{10}\) \(\frac{6 \times 9}{27}\)
= log\(_{10}\)2

15.

Bala sold an article for #6,900.00 and made a profit of 15%. Calculate his percentage profit if he had sold it for N6,600.00.

A. 5%

B. 10%

C. 12%

D. 13%

Detailed Solution

15 = (\(\frac{6,900 - C.P \times 100}{C.P}\))
15 C.P = 690000 - C.P 100
C.P = \(\frac{690000}{115}\)
C.P = N6,000
%profit = \(\frac{6,600 - 6,000}{6,000}\) x 100
= \(\frac{600}{6,000}\) x 100
= 10%
16.

If 3p = 4q and 9p = 8q - 12, find the value of pq.

A. 12

B. 7

C. -7

D. -12

Detailed Solution

9p = 8q - 12
9p = 2(4q) - 12
9p = 2(3q) - 12
9p = 6p - 12
3p = -12
p = -4
\(\frac{3 \times -4}{4} = \frac{4q}{4}\)
q = 13
pq = -3 x -4
= 12
17.

If (0.25)\(^y\) = 32, find the value of y.

A. y = - \(\frac{5}{2}\)

B. y = -\(\frac{3}{2}\)

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

D. y = \(\frac{5}{2}\)

Detailed Solution

(0.25)\(^y\) = 32
2\(^{-2y}\) = 3\(^{2}\)
2 - 2y = 5
y = - \(\frac{5}{2}\)
18.

There are 8 boys and 4 girls in a lift. What is the probability that the first person who steps out of the lift will be a boy?

A. \(\frac{1}{6}\)

B. \(\frac{1}{4}\)

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

D. \(\frac{1}{2}\)

Detailed Solution

Total number of people in the lift = 8 boys + 4 girls
= 12 people
probability that a boy comes out = \(\frac{8}{12}\) = \(\frac{2}{3}\)
19.

Simplify: \(\frac{x^2 - 5x - 14}{x^2 - 9x + 14}\)

A. \(\frac{x - 7}{x + 7}\)

B. \(\frac{x + 7}{x - 7}\)

C. \(\frac{x - 2}{x + 4}\)

D. \(\frac{x + 2}{x - 2}\)

Detailed Solution

\(\frac{x^2 - 5x - 14}{x^2 - 9x + 14}\)
\(\frac{(x - 7)(x + 2)}{(x - 7)(x - 2)}\)
= \(\frac{x + 2}{x - 2}\)
20.

Which of these values would make \(\frac{3p^-}{p^{2-}}\) undefined?

A. 1

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

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

D. -1

Detailed Solution

P\(^2\) - p = 0
p(p - 1) = 0
p = 0 or p = 1
11.

If m : n = 2 : 1, evaluate \(\frac{3m^2 - 2n^2}{m^2 + mn}\)

A. \(\frac{4}{3}\)

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

C. \(\frac{3}{4}\)

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

Detailed Solution

m = 2, n = 1
\(\frac{3m^2 - 2n^2}{m^2 _ mn}\)
= \(\frac{3(2)^2 - 2(1)^2}{2^2 + 2(1)}\)
= \(\frac{12 - 2}{4 + 2} = \frac{10}{6}\)
= \(\frac{5}{3}\)
12.

H varies directly as p and inversely as the square of y. If H = 1, p = 8 and y = 2, find H in terms of p and y.

A. H = \(\frac{p}{4y^2}\)

B. H = \(\frac{2p}{y^2}\)

C. H = \(\frac{p}{2y^2}\)

D. H = \(\frac{p}{y^2}\)

Detailed Solution

H \(\propto\) \(\frac{p}{y^2}\)
H = \(\frac{pk}{y^2}\)
1 = \(\frac{8k}{2^2}\)
k = \(\frac{4}{8}\)
= \(\frac{1}{2}\)
H = \(\frac{p}{2y^2}\)
13.

Solve 4x^{2}\) - 16x + 15 = 0.

A. x = 1\(\frac{1}{2}\) or x = -2\(\frac{1}{2}\)

B. x = 1\(\frac{1}{2}\) or x = 2\(\frac{1}{2}\)

C. x = 1\(\frac{1}{2}\) or x = -1\(\frac{1}{2}\)

D. x = -1\(\frac{1}{2}\) or x -2\(\frac{1}{2}\)

Detailed Solution

4x\(^2\) - 16x + 15 = 0
(2x - 3)(2x - 5) = 0
x = 1\(\frac{1}{2}\) or x = 2\(\frac{1}{2}\)
14.

Simplify: \(\log_{10}\) 6 - 3 log\(_{10}\) 3 + \(\frac{2}{3} \log_{10} 27\)

A. 3 \(\log_{10}^2\)

B. \(\log_{10}^2\)

C. \(\log_{10}^3\)

D. 2 \(\log_{10}^3\)

Detailed Solution

log\(_{10}\) 6 - log\(_{10}\)3\(^3\) + log\(_{10}\) (\(\sqrt[3]{27}\))\(^2\)
= log \(_{10}\) 6 - log \(_{10}\) 27 + log\(_{10}\) 9
= log\(_{10}\) \(\frac{6 \times 9}{27}\)
= log\(_{10}\)2

15.

Bala sold an article for #6,900.00 and made a profit of 15%. Calculate his percentage profit if he had sold it for N6,600.00.

A. 5%

B. 10%

C. 12%

D. 13%

Detailed Solution

15 = (\(\frac{6,900 - C.P \times 100}{C.P}\))
15 C.P = 690000 - C.P 100
C.P = \(\frac{690000}{115}\)
C.P = N6,000
%profit = \(\frac{6,600 - 6,000}{6,000}\) x 100
= \(\frac{600}{6,000}\) x 100
= 10%
16.

If 3p = 4q and 9p = 8q - 12, find the value of pq.

A. 12

B. 7

C. -7

D. -12

Detailed Solution

9p = 8q - 12
9p = 2(4q) - 12
9p = 2(3q) - 12
9p = 6p - 12
3p = -12
p = -4
\(\frac{3 \times -4}{4} = \frac{4q}{4}\)
q = 13
pq = -3 x -4
= 12
17.

If (0.25)\(^y\) = 32, find the value of y.

A. y = - \(\frac{5}{2}\)

B. y = -\(\frac{3}{2}\)

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

D. y = \(\frac{5}{2}\)

Detailed Solution

(0.25)\(^y\) = 32
2\(^{-2y}\) = 3\(^{2}\)
2 - 2y = 5
y = - \(\frac{5}{2}\)
18.

There are 8 boys and 4 girls in a lift. What is the probability that the first person who steps out of the lift will be a boy?

A. \(\frac{1}{6}\)

B. \(\frac{1}{4}\)

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

D. \(\frac{1}{2}\)

Detailed Solution

Total number of people in the lift = 8 boys + 4 girls
= 12 people
probability that a boy comes out = \(\frac{8}{12}\) = \(\frac{2}{3}\)
19.

Simplify: \(\frac{x^2 - 5x - 14}{x^2 - 9x + 14}\)

A. \(\frac{x - 7}{x + 7}\)

B. \(\frac{x + 7}{x - 7}\)

C. \(\frac{x - 2}{x + 4}\)

D. \(\frac{x + 2}{x - 2}\)

Detailed Solution

\(\frac{x^2 - 5x - 14}{x^2 - 9x + 14}\)
\(\frac{(x - 7)(x + 2)}{(x - 7)(x - 2)}\)
= \(\frac{x + 2}{x - 2}\)
20.

Which of these values would make \(\frac{3p^-}{p^{2-}}\) undefined?

A. 1

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

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

D. -1

Detailed Solution

P\(^2\) - p = 0
p(p - 1) = 0
p = 0 or p = 1