conversations.from: human
conversations.value: Tony exercises every morning by walking 3 miles carrying a 25-pound backpack, then he runs another 10 miles without the backpack.  If he walks at a speed of 3 miles per hour and runs at a speed of 5 miles per hour, how many hours each week does he spend exercising?
  What is the solution?
conversations.from: assistant
conversations.value: Tony walks 3 miles at 3 miles per hour for 3/3=1 hour.
  Tony also runs 10 miles at 5 miles per hour for 10/5=2 hours.
  Thus, each day he exercises for 1+2=3 hours.
  Over the course of one week, he exercises for 3*7=21 hours.