Problem Solving

Question

William cycles at a speed of 15 miles per hour . He cycles 12 miles from home to school . If he increases his cycling speed by 5 miles per hour , how much faster will he reach his school

Answer 1

15 * t = 12

t = 12/15 = 4/5 hr = 48 min

vs

20 * t = 12

t = 12/20 = 6/10 = 3/5 hr = 36 min

12 minutes faster = 12/60 hr = 1/5 hr