Aboy leaves on a bicycle trip at the rate of 8 mph. one hour later the father, realizing that his son forgot his camping gear, sets out by car. how fast must the father drive to overtake the boy in 15 minutes?

  1st equation to find out how far boy will have traveled in 1hr 15 minutes:

8/1=x/1.25 (8 miles over 1 hour = x miles over 1.25 hours)
8(1.25) = 1(x)
10 = x

Now, divide 10 by .25 (15 minutes aka 1/4 hour) to get the speed father will have to drive.

10/.25 = x/1

x = 40 MPH