WAEC Past Questions and Answers - Page 4245

21,221.

A student measured the length of a room and obtained the measurement of 3.99m. If the percentage error of is measurement was 5% and his own measurement was smaller than the length , what is the length of the room?

A.

3.78m

B.

3.80m

C.

4.18m

D.

4.20m

E.

4.788m

Correct answer is D

Let the actual length of the room = y m

\(\therefore \frac{y - 3.99}{y} \times 100% = 5%\)

\(100(y - 3.99) = 5y \implies 100y - 399 = 5y\)

\(100y - 5y = 399 \implies y = \frac{399}{95}\)

y = 4.2 m

21,222.

If log\(_{10}\) a = 4; what is a?

A.

0.4

B.

40

C.

400

D.

1000

E.

10000

Correct answer is E

log\(_{10}\) a = 4

a = 10\(^4\)

= 10000

21,223.

Simplify 0.63954 ÷ 0.003 giving your answer correct to two significant figures

A.

213.18

B.

213.00

C.

213

D.

210

E.

21

Correct answer is D

= \(\frac{0.63954}{0.003}\) 

moving the decimal places, we have

= \(\frac{639.54}{3}\)

= 213.18

\(\approxeq\) 210 (to 2 s.f.)

21,224.

Cos x is negative and sin x is negative.Which of the following is true of x?

A.

0o < x < 90o

B.

90o < x <180o

C.

180o < x < 270o

D.

270o < x <360o

E.

-90o < x <90o

Correct answer is C

In the 3rd quadrant, only the tan of angles are positive.

The 3rd quadrant = 180° < x < 270°

21,225.

If log\(_{10}\) q = 2.7078, what is q?

A.

5102

B.

849.9

C.

510.2

D.

84.99

E.

51.02

Correct answer is C

q = 10\(^{2.7078}\)

Antilog of 2.7078 = 510.2