WAEC Mathematics Past Questions & Answers - Page 54

266.

One factor of \(7x^2 + 33x - 10\) is

A.

7x + 5

B.

x - 2

C.

7x - 2

D.

x - 5

Correct answer is C

\(7x^2 + 33x - 10\)

\(7x^2 + 35x - 2x - 10\)

7x (x + 5) - 2 (x + 5)

(7x - 2) (x + 5)

267.

A sum of N18,100 was shared among 5 boys and 4 girls with each boy taking N20.00 more than each girl. Find a boy's share.

A.

N1,820.00

B.

2,000.00

C.

N2,020.00

D.

N2,040.00

Correct answer is C

Let a girl's share = x + 20

4x + 5(x + 20) = 18,100

4x + 5x + 100 = 18,100

9x + 100 = 18,100

9x = 18,000

x = \(\frac{18,000}{9}\)

x = 2,000

\(\therefore\) Each boy gets N(2,000 + 20)

 = N2,020.

268.

Solve the equation: \(\frac{1}{5x} + \frac{1}{x}\)= 3

A.

\(\frac{1}{5}\)

B.

\(\frac{2}{5}\)

C.

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

D.

\(\frac{4}{5}\)

Correct answer is B

\(\frac{1}{5x} + \frac{1}{x}\)= 3

\(\frac{1 + 5}{5x}\) = 3

6 = 15x

x = \(\frac{6}{15}\)

= \(\frac{2}{5}\)

269.

If x = \(\frac{2}{3}\) and y = - 6, evaluate xy - \(\frac{y}{x}\)

A.

0

B.

5

C.

8

D.

9

Correct answer is B

x = \(\frac{2}{3}\) and y = - 6

xy - \(\frac{y}{x}\)

\(\frac{2}{3} - (6)^2 - (-6) \div \frac{2}{3}\)

= -4 - (6) x \(\frac{3}{2}\)

= -4 - (-6) x \(\frac{3}{2}\)

= -4 - (-9)

= -4 + 9

= 5

270.

Given that a = log 7 and b = \(\log\) 2, express log 35 in terms of a and b.

A.

a + b + 1

B.

ab - 1

C.

a - b + 1

D.

b - a + 1

Correct answer is C

\(\frac{\log 7 \times \log 10}{\log 2}\)

log 7 x log 10 \(\div\) log 2

a + 1 - b

a - b + 1