Question

A bus travels a distance of 180 km with a speed of 60 km/hr and returns with the speed of 30 km/hr. Calculate the average speed for the entire journey.

Answer 1

SoluTion :-

$\sf {\frac{2}{V_{avg.}} = \frac{1}{V_1} + \frac{1}{V_2} }\\\\\\\sf {\frac{2}{V_{avg.}}= \frac{1}{60} + \frac{1}{30} }\\\\\\\sf {\frac{2}{V_{avg.}}= \frac{1+2}{60} }\\\\\\\sf {\frac{2}{V_{avg.}}=\frac{1}{20}}\\\\\\\\\sf {V_{avg.}=2 \times 20}\\\\\\\sf {V_{avg.}=40\ km/hr}$