WAEC Mathematics Past Questions & Answers - Page 224

1,116.

If the interior angles of hexagon are 107°, 2x°, 150°, 95°, (2x-15)° and 123°, find x.

A.

\(57\frac{1}{2}^{\circ}\)

B.

\(65^{\circ}\)

C.

\(106^{\circ}\)

D.

\(120^{\circ}\)

Correct answer is B

Sum of interior angle in a hexagon = (6 - 2) x 180°

= 720°

\(\therefore\) 107° + 2x° + 150° + 95° + (2x - 15)° + 123° = 720°

460 + 4x = 720 \(\implies\) 4x = 720 - 460

4x = 260° \(\implies\) x = 65°

1,117.
1,118.

In the diagram, PQRS is a circle center O. PQR is a diameter and ∠PRQ = 40°. Calculate ∠QSR

A.

30o

B.

40o

C.

45o

D.

50o

Correct answer is D

< Q = < R (OQ = OR = radii)

< QOR = 180° - 2(40°) = 100°

< QSR = < RPQ = \(\frac{1}{2}\) < QOR

= \(\frac{100}{2} = 50°\)

1,120.

The probabilities that Kodjo and Adoga pass an examination are \(\frac{3}{4}\) and \(\frac{3}{5}\) respectively. Find the probability of both boys failing the examination

A.

\(\frac{1}{10}\)

B.

\(\frac{3}{10}\)

C.

\(\frac{9}{20}\)

D.

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

Correct answer is A

P(Kodjo passing) = \(\frac{3}{4}\); P(Adoga passing) = \(\frac{3}{5}\)

P(Kodjo failing) = \(\frac{1}{4}\); P(Adoga failing) = \(\frac{2}{5}\)

P(both fail) = \(\frac{1}{4} \times \frac{2}{5}\)

= \(\frac{1}{10}\)