Answer:
24
Explanation:
If the total amount that I earn for the summer is constant, then the number of hours I work each week and the total number of weeks that I work are inversely proportional. Consequently, if I only work 10/12=5/6 as many weeks, I need to work 6/5 as many hours each week. 6/5 times 20=24, so I need to work 24 hours a week.