Question

William cycles at a speed of 15 miles per hour. he cycles for 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

12/15=4/5 original speed
12/20=3/5 increase by 5mph
He will reach 12 minutes earlier than he goes 15 miles per hour.
Correct me if I am wrong.