WAEC Past Questions and Answers - Page 3065

15,321.

Which of the following is a factor of 2 - x - x2?

A.

1 - x

B.

1 + x

C.

x - 1

D.

2 - x

Correct answer is A

2 - x - x2; (2 - 2x) + (x - x2)

= 2(1 - x) + x(1 - x)

= (1 - x)(2 + x)

= 1 - x

15,322.

PQR is an equilateral triangle with sides 2\(\sqrt{3cm}\). calculate its height

A.

1.7cm

B.

3.0cm

C.

3.2cm

D.

3.9cm

Correct answer is B

By Pythagoras theorem

h2 = (2\(\sqrt{3})^2 - (\sqrt{3})^2\)

= 22(\(\sqrt{3})^2 - 3\)

4(3) - 3 = 112 - 3

h2 = 9

h = \(\sqrt{9}\)

= 3cm

15,323.

At what rate per cent per annum will N520.00 yield a simple interest of N39.00 in three years?

A.

4%

B.

3\(\frac{1}{2}\)%

C.

3%

D.

2\(\frac{1}{2}\)%

Correct answer is D

SI = \(\frac{PRT}{100}\)

39 = \(\frac{520 \times R \times 3}{100}\)

1560R = 3900

R = \(\frac{3900}{1560}\)

= 2.5%

R = 2\(\frac{1}{2}\)%

15,324.

A messenger was paid N2.50 an hour during the normal working hours and 4.00 n hour during overtime. If he received N31.00 for 10 hours work, how many hours are for overtime?

A.

2

B.

3

C.

4

D.

6

Correct answer is C

Let normal working hour = x

let overtime = y

after 10 hours = N31.00

1 x 2.50x + 4y = 31

4 x x + y = 10

2.50x + 4y = 31
- 4x + 4y = 30
----------------
-1.5x = -9

x = 6; x + y = 10

6 + y = 10

y = 10 - 4

y = 4hrs for over time

15,325.

Find the value of a if log\(_{10}\) a + log\(_{10}\)a\(^2\) = 0.9030

A.

4.0

B.

2.0

C.

1.6

D.

0.0

Correct answer is C

log\(_{10}\) a + log\(_{10}\)a\(^2\) = 0.9030

log (a x a\(^2\)) = 0.9030

log a\(^3\) = 0.9030

a\(^3\) = 10^.9030(antilogarithm table)

a\(^3\) = 7.998

a = 3\(\sqrt{7.998}\)

a = 1.6