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?
She earned $42.5 on average per week because 425 / 10 = <<425/10=42.5>>42.5
She earned $22.5 each week from extra chores because 42.5 - 20 = <<42.5-20=22.5>>22.5
She did 15 extra chores a week because 22.5 / 1.5 = <<22.5/1.5=15>>15
#### 15