Question

John studied for 22.5 hours over a period of 3.5 days. On average, about how many hours did he study each day?

Answer 1

22.5 hours divided by the # of days (3.5) gives you the average per day. think about it: you are dividing the total # of hours, 22.5, into the total days (3.5). so the answer is 22.5/3.5
also, a good way to check yourself via the "common sense method" is to see if this makes sense. if 22.5 is the total # of hours, the the hours per day should be less. 22./53.5=6.428, which is less. yay!