SOLUTION: A car travels from A and B at 30kph,from B to C at 40kph and from C to A at 50kph.If A,B and C are equidistant from each other, determine the average speed of the car for the enti

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Question 1143808: A car travels from A and B at 30kph,from B to C at 40kph and from C to A at 50kph.If A,B and C are equidistant from each other, determine the average speed of the car for the entire trip by using the harmonic lean formula.
Answer by ikleyn(53765) About Me  (Show Source):
You can put this solution on YOUR website!
.
The entire distance consists of three segments of the length  d = |AB|,  d = |BC|  and  2d = |CA|.


Hence, the average speed of the car at the entire journey is


    average speed = %28d+%2B+d+%2B+2d%29%2F%28d%2F30+%2B+d%2F40+%2B+2d%2F50%29 = 4%2F%281%2F30+%2B+1%2F40+%2B+2%2F50%29 = 4%2F%2820%2F600+%2B+15%2F600+%2B+24%2F600%29 = %284%2A600%29%2F%2820+%2B+15+%2B+24%29 = %284%2A600%29%2F59 = 40.678 kilometers per hour (approximately)