M4maths Previous Puzzles

18 Aug 2022 Time Distance & Speed

A bus covers a certain distance at an average speed of 80 kmph without any stoppages. While returning the same journey the bus covers the distance at an average speed of 60 kmph with stoppages. What is the average stoppage time per hour taken by the bus?

OPtion

1) 18 minutes
2) 20 minutes
3) 12 minutes
4) 40 minutes
5) 24 minutes
6) 10 minutes
7) 28 minutes
8) 15 minutes
9) 30 minutes
10) None of these

Solution

Let’s assume the total journey distance in either direction is 'D' km
Therefore, time taken for the onward journey = D/80 hrs
And time taken for the return journey = D/60 hrs
The difference in journey time indicates the stoppage time = (D/60)-(D/80) = D/240 hrs
In the journey of D/60 hrs, stoppage time is D/240 hrs
Therefore, the average stoppage time per hour = (D/240)/ (D/60) hrs = 1/4 hrs = 15 minutes.
Correct Option 8)

Correct Option: 8 Best Solution (0)