Question

a car travels a certain distance with a speed of 50km/h and returns with a speed of 40km/h . Calculate the average velocity of the car for the whole journey
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Answer 1

Answer:

44.44km/h

Explanation:

Let the whole distance be x

Time taken in the forward journey at a speed of 50km/h = $\frac{distance}{speed}=\frac{x}{50}$h

Time taken in the return journey at a speed of 40km/h =$\frac{x}{40}h$

Total time for the whole journey =

                                                            $\frac{x}{50}+\frac{x}{40} \\taking L.C.M\\\frac{4x}{200} +\frac{5x}{200}\\\frac{9x}{200}h$

Total distance covered = x+x =2x

$average speeed =\frac{total distance }{total time } \\ =\frac{2x}{\frac{9x}{200} }\\=\frac{2x*200}{9x}\\=\frac{400}{9} \\=44.44km/h$