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 ?
"due to stoppages , it covers 9 km less . time taken to cover 9 km = ( 9 / 54 x 60 ) min = 10 min . answer : b"
multiply(const_60, divide(subtract(54, 45), 54))