1995 - WAEC Mathematics Past Questions and Answers - page 5

Note: sin 20° = cos 70° hence

\(\frac{\sin 20}{\cos 70} = 1\)

Also, cos 65° = sin 25°

\(\frac{\cos 65}{\sin 25} = 1\)

\(\therefore \frac{\sin 20}{\cos 70} + \frac{\cos 65}{\sin 25}\)

= 1 + 1

= 2

\(\sin 30° = \frac{y}{10}\)

\(y = 10 \sin 30° = 10 \times 0.5 = 5 cm\)

x\(^2\) = 12\(^2\) + 5\(^2\)

x\(^2\) = 144 + 25

x\(^2\) = 169

x = \(\sqrt{169}\) = 13m.

The mode = 8 with the highest frequency of 4 times.

Mean of 20 observations = 4

All the observations = 20 x 4 = 80

Largest observed value = 23

Remaining observation = 80 - 23 = 57

Mean of observation = 57/19 = 3

Arranging the numbers in ascending order, we have

2.35, 2.50, 2.64, 2.72, 2.91.

The median = 2.64