Question 95270
John walked from point P to point Q and back again, a total distance of 2 miles. If he averaged 4 miles per hour on the trip from P to Q and 5 miles per hour on the return trip, what was his average walking speed for the entire trip?
:
We want to find out the total time it took him to walk the total distance, then
it is an easy calculation to find the average speed
:
Time = Dist/speed
:
One way distance = 1 mile
:
To time + return time = Total time
{{{1/4 + 1/5}}} = {{{(5 + 4)/20}}} = {{{9/20}}} = .45 hrs to walk the two miles
:
Speed = dist/time
Av speed = {{{2/.45}}} = 4.44 mph