SOLUTION: If my driver is driving my car to school which is 5 k away from home at 40 km/hr (because you’re in the car) then returns home at 100 km/hr, what is his average speed?

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: If my driver is driving my car to school which is 5 k away from home at 40 km/hr (because you’re in the car) then returns home at 100 km/hr, what is his average speed?       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 1061326: If my driver is driving my car to school which is 5 k
away from home at 40 km/hr (because you’re in the
car) then returns home at 100 km/hr, what is his
average speed?

Answer by jorel555(1290) About Me  (Show Source):
You can put this solution on YOUR website!
5k @ 40 kph=1/8th hours=5/40ths hours
5k @ 100 kph=1/20th hours=2/40ths hours
Your total travel time is 7/40ths of an hour to go 10 km. So the average for the whole trip is 10/(7/40) kph, or 57.1429 kph. ☺☺☺☺