WAEC Mathematics Past Questions & Answers - Page 249

1,241.

Solve the equation 5x2 - 4x - 1 = 0

A.

-1, 1/5

B.

-1, -1/5

C.

1, 1/5

D.

1, -1/5

E.

-1, 5

Correct answer is D

5x2 - 4x - 1 = 0
5x2 5x + x -1 = 0
5x(x - 1) + (x - 1) = 0
(5x + 1)(x -1) = 0
x = -1/5 or 1 = 0

1,242.

Simplify \(\frac{8^{\frac{2}{3}}*27^{\frac{-1}{3}}}{64^{\frac{1}{3}}}\)

A.

-3

B.

\(\frac{1}{9}\)

C.

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

D.

\(\frac{27}{8}\)

E.

4

Correct answer is C

\(\frac{8^{\frac{2}{3}}*27^{\frac{-1}{3}}}{64^{\frac{1}{3}}}\)
\(\frac{2^2*3^{-3}}{4} = 3^{-1} = \frac{1}{3}\)

1,243.

A piece of cloth was measured as 6.10m. If the actual length of the cloth is 6.35, find the percentage error, correct to 2 decimal places

A.

3.05%

B.

3.95%

C.

15.00%

D.

25.00%

E.

39.30%

Correct answer is B

No explanation has been provided for this answer.

1,244.

Find the number whose logarithm to base 10 is 2.6025

A.

0.0004

B.

4.004

C.

40.04

D.

400.4

E.

4004

Correct answer is D

No explanation has been provided for this answer.

1,245.

The nth term of a sequence is represented by 3 x 2(2-n). Write down the first three terms of the sequence

A.

3/2, 3, 6

B.

6, 3, 3/2

C.

3/2, 3, 1/3

D.

2/3, 3, 8/3

E.

3/2, 0, 6

Correct answer is B

When n = 1, n = 2, n = 3
3 x 22 - 1 = 6
3 x 22 - 2 = 3
3 x 22 - 3 = 3/2