excluding stoppages , the speed of a bus is 40 kmph and including stoppages , it is 30 kmph . for how many minutes does the bus stop per hour ?
"due to stoppages , it covers 10 km less . time taken to cover 10 km = ( 10 / 40 x 60 ) min = 15 min answer : d"
multiply(const_60, divide(subtract(40, 30), 40))