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 ?

** Option:**

**A.**20

**B.**12

**C.**10

**D.**9

**Answer: C . 10**

** Justification:**

Due to stoppages, it covers 9 km less.

Time taken to cover 9 km

= (9/54) * 60 min **= 10 min**