Answer:
7/24
Explanation:
Th question doesn't give enough information. Is it that 17 girls watched the tennis? Let's assume that's the question.
If there are 20 boys in total, this means there 36 girls in total.
This means if 17 girls watched then 19 did not watch.
If in total all those that didn't watch is 32 and 19 girls did not watch, then 13 boys did not watch.
We are left with 7 boys watched and 17 girls watched and in total 24 students watched.
The probability that if a student is chosen at random a boy will be chosen will be:
7/24.