Question

160 pupils in a sports centre are surveyed. The pupils can only use the swimming pool, the gym and the tennis courts. 21 pupils use the swimming pool, the gym and the tennis courts. 55 pupils use the swimming pool and the gym. 48 pupils use the gym and the tennis courts. 40 pupils use the tennis courts and the swimming pool. 11 pupils use the swimming pool only. 7 pupils use the gym only. 35 pupils use the tennis courts only. Find the probability to select a pupil that uses the tennis courts.

Answer 1

0.6375 = 63.75% probability to select a pupil that uses the tennis courts.

Explanation:

A probability is the number of desired outcomes divided by the number of total outcomes.

Total:

In total, there are 160 pupils.

Uses the tennis courts:

21 pupils use the swimming pool, the gym and the tennis courts.

48 pupils use the gym and the tennis courts, which adds 48 - 21 = 27 to the number of those who use the tennis courts.

40 pupils use the tennis courts and the swimming pool, which adds 40 - 21 = 19 to the number of those who use the tennis courts.

35 use the tennis courts only.

So

21 + 27 + 19 + 35 = 102 use the tennis courts.

Find the probability to select a pupil that uses the tennis courts.

102 out of 160, so:

`p = (102)/(160) = 0.6375`

0.6375 = 63.75% probability to select a pupil that uses the tennis courts.