The task is to generate the correct answer for a given math problem.

Q: Problem: the average of first 22 natural numbers is ?

A: 11.5
****
Q: Problem: if 2 men or 3 women can reap a field in 10 days how long will 4 men and 5 women take to reap it ?

A: 11 / 30
****
Q: Problem: if john makes a contribution to a charity fund at school , the average contribution size will increase by 50 % reaching $ 75 per person . if there were 3 other contributions made before john ' s , what is the size of his donation ?

A:
$ 150
****