A motorist travels to a place 150 km away at an average speed of 50 km/hr and returns at 30 km/ hr. His average speed for the whole journey in km/hr is.
A. 35 km/hr
B. 37 km/hr
C. 37.5 km/hr
D. 40 km/hr
Show Answer
Answer-C
Solution-
Solution(By Apex Team)
$\begin{array}{l}\text{ Average speed }\\
=\left(\Large\frac{2xy}{x+y}\right)\mathrm{km}/\mathrm{hr}\\
=\left(\Large\frac{2\times50\times30}{50+30}\right)\mathrm{km}/\mathrm{hr}\\
=37.5\mathrm{~km}/\mathrm{hr}\end{array}$
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