Excluding stoppages, the speed of a bus is 54 kmph and including stoppages, it is 36 kmph. For how many minutes does the bus stop per hour?	Choose the correct choice from the following answers:
A) 20 min	B) 8 min	C) 9 min	D) 10 min	E) 11 min

Rationale: "due to stoppages , it covers 18 km less . time taken to cover 18 km = ( 18 / 54 ) x 60 = 20 min answer : a"
Answer: A