WAEC 2022 · Paper 1 · Q22

The table shows the distribution of the distance (in km) covered by 40 hunters while hunting.

Distance (km)	3	4	5	6	7	8
Frequency	5	4	$x$	9	$2x$	1

If a hunter is selected at random, find the probability that the hunter covered at least 6 km.

Worked solution (try it first)

The frequencies add up to 40: $5 + 4 + x + 9 + 2x + 1 = 40$ , so $3x + 19 = 40$ and $x = 7$ .
At least 6 km means 6, 7 or 8 km: $9 + 2(7) + 1 = 24$ hunters.
So the probability is $\dfrac{24}{40} = \dfrac{3}{5}$ , option A.