Question

In a class of 32 students, the mean height of the 14 boys is 1.56 metres. The mean height of all 32 students is 1.515 metres.

Work out the mean height of the girls.

Answer 1

1.48 m

Explanation:

mean height of 14 boys is 1.56 m, so their total height is 14 * 1.56 = 21.84 m

mean height of 32 students is 1.515 m, so their total height is 48.48

48.48 - 21.84 = 26.64 (total height of the girls)

mean height of the girls is 26.64/18 = 1.48 m

Answer 2

1.48 m.

Explanation:

There are 32 - 14 = 18 girls in the class.

Total height of the whole class = 1.515 * 32

= 48.48 m..

Total height of all the boys = 14 * 1.56 = 21.84 m.

So the total height of the 18 girls = 48.48 - 21.84

= 26.64 m.

Therefore the mean height of the girls

= 26.64 / 18

= 1.48 m.