Ok so you could use the equation h=t divided by w. h represents the hours volunteered in one week. t represents the amount of hours volunteered in the original amount of weeks. w represents the original amount of weeks. When you plug In the numbers you get h=72 divided by 12 which gives you h=6 so Penn volunteered 6 hours in one week. You know the answer is reasonable because there are 168 hours in a week, so Penn could easily spend 6 hours a week volunteering. Sorry if my explanation is confusing, but I tried to help. Good luck :)
Automatically we know that he is wrong because even if we round it to make it a friendly number (lets say 1) it will still not equal 3 1/2 he has them for 3 1/2 days
even 1+1+1= 3 it still isnt enough and you arent even supposed to round
