1.  Excluding stoppages, the speed of a bus is 54 kmph and including stoppages, it is 45 kmph. For how many minutes does the bus stop per hour ?
A. 9
B. 10
C. 12
D. 20

Answer: Option B

Explanation:

Due to stoppages, it covers 9 km less.

∴ Time taken to cover 9 km = (9/54 x 60) min = 10 min.