Mrs. Leithold boarded a bus bound for California at exactly 4 A.M. After one-half hours her husband followed driving the family car at 75 mph. Assuming that the bus was travelling at an average speed of 50 mph, at what time would Mr. Leithold's car overtake the bus?

Solution:

The time from 4:30AM is x

So

50*(1/2) = (75-50)x

x = 1

So Mr. Leithold's car overtake the bus at 5:30AM