Excluding stoppages, the speed of the bus is 54 kms /hr and with stoppages, it is 45 kmph. For how many minutes does the bus stop per hour?
Choose the most appropriate option:
A) 9	B) 10	C) 11	D) 12	E) 20

Rationale: by including stoppages , bus will cover 9 km less . . ( 54 km - 45 km = 9 km ) excluding stoppages , x = 54 kmph including stoppages , y = 45 kmph difference , z = 9 km time taken to cover that 9 km ( bus stops per hour ( 60 minutes ) ) = z / x ( 60 minutes ) = 9 / 54 ( 60 ) = 1 / 6 ( 60 ) = 10 minutes . answer : b
Answer: B