Question

What is the average speed of a train that travels from one station to another station at a uniform speed of 40kmph and returns to the initial station at 60kmph.

• A. 40km/h
• B. 60km/h
• C. 48km/h
• D. 12km/h

Answer 1

The correct option is C

48km/h

➡Complete solution:-

➡Let the distance between two stations = $dkm$

➡After, the journey the train returns to the first station.

➡Total distance travelled = $2d$

➡So, the time taken by train to travel from one station to another station = $t_1=\frac{d}{40}hrs$

Time taken by the train for the return journey, $t_2=\frac{d}{60}hrs$

Therefore, the total time taken by the train for the round the trip is

$t=t_1+t_2=\frac{d}{40}+\frac{d}{60}=\frac{d}{24}hrs$

➡Avg . Speed = $\frac{totaldistancecovered}{totaltimetaken}$ = $\frac{2d}{\frac{d}{24}}=48km/h$