Posted by donna on Sunday, March 7, 2010 at 10:14pm.
a truck driver traveled at an average speed of 48 miles per hour on a 100mile trip to pick up a load of freight. On the return trip with the truck fully loaded,the average speed was 40 miles per hour. Find the average speed for the round trip.

math  Reiny, Sunday, March 7, 2010 at 10:50pm
time for first trip = 100/48 hours = 25/12 hrs
time for return trip = 100/40 = 5/2 hours
total time = 5/2 + 25/12 hours = 55/12 hrs
avg speed = total distance / total time
= 200/(55/12) = 43.64 mph