Carol gets a fixed $20 allowance each week. She can also earn $1.5 more dollars each week if she does extra chores. At the end of 10 weeks, she has 425 dollars. How many extra chores did she average each week? Think carefully first, then make a decision:
She earned $42.5 on average per week because 425 / 10 = 42.5. She earned $22.5 each week from extra chores because 42.5 - 20 = 22.5. She did 15 extra chores a week because 22.5 / 1.5 = 15. So, the answer is 15.