SOLUTION: A car averages 80km/h to the city. On the way back it averages 120km/h. What is the average speed of the whole trip?

Question 813544: A car averages 80km/h to the city. On the way back it averages 120km/h. What is the average speed of the whole trip?
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
A car averages 80km/h to the city. On the way back it averages 120km/h. What is the average speed of the whole trip?
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Find the total time for the round trip.
d = r*t
t = d/r
t = d/80 + d/120
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Total distance = 2d
RT avg = 2d/t
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RT avg = 2*80*120/(80 + 120)
= 96 km/hr
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