Posted by Brad Paul on October 30, 2002 at 16:04:58:
In Reply to: Distance/Speed posted by Randy on October 30, 2002 at 15:39:00:
: A person descends a hill at 3 miles per hour. She climbs the hill at 1 mile per hour. The trip takes 40 minutes. How far does she walk and was is her average speed?
: Please show step by step. Thanks for your help.
The distance out is the same as the distance back. Let this be d. The
total time of the trip is t.
How much time was spent traveling at v1?
t1=d/v1
How much time was spent traveling at v2?
t2=d/v2
What was the total time?
t=t1+t2=d/v1+d/v2
Solve for d.
What was the total distance traveled?
dtotal=2 d
What was the average speed?
vavg=dtotal/t=(2 d)/t