Correct option is C
GIVEN:
that excluding stoppages, the speed of a bus is 80 kmph
stoppages the speed of the bus is 52km/hr.
Distance travelled by bus in one hour excluding stoppages – distance travelled
bus in one hour including stoppages = 80 -52 = 28 KM
Time taken to cover 28 km = DISTANCE/SPEED
Usual speed of the bus =80 km/hr
Time to cover 28 km = 28/80
Time taken in minute=28/80 × 60
=7/20 × 60
=7 × 3= 21