Percy swims 1 hour before school and 1 after school 5 days a week.  He swims 3 hours on the weekend.  How many hours of swimming does he do over 4 weeks?
He swims 1 hour before and after school for a total of 1+1 = <<1+1=2>>2 hours
He swims 2 hours a day for 5 days for a total of 2*5 = <<2*5=10>>10 hours
He also swims an additional 3 hours on the weekend so 10+3 = <<10+3=13>>13 hours
Over a course of 4 weeks, at 13 hours per week, he swims 4*13 = <<4*13=52>>52 hours
#### 52