Question

You drive 150 miles in 3 hours before stopping for 30 minutes to have lunch and gas.  After lunch you travel 100 miles in an hour and a half.  What was your average speed?

Answer 1

Average speed = total miles driven / total driving time
average speed = (150 + 100) / (3 + 1 1/2) =
                             250 / (4 1/2) =
                             250 / (9/2) =
                             250 * 2/9 =
                             500 / 9 = 55.55 mph