Question

Sabu got into the bus at 6 o’clock. Usually the bus travels at an average speed of 30 km/hr and reaches the railway station at ten. But that day, it was raining and it could manage only an average speed of 20 km/hr. Sabu got down from the bus at eight and caught a car. He reached the station at ten itself. What was the average speed of the car?

Answer 1

Usual average speed of the bus = 30 km/h

Time taken by the bus to reach the railway station = 4 hours (from 6 o’clock to 10 o’clock)

We know that distance travelled = Average speed × time taken

∴ Distance covered by the bus = (30 × 4) km = 120 km

On the rainy day, the average speed of the bus = 20 km/h

Time taken by the bus = 2 hours (from 6 o’clock to 8 o’clock)

∴ Distance covered by the bus in 2 hours = (20 × 2) km = 40 km

Remaining distance covered by the car in 2 hours (from 8 o’clock to 10 o’clock)

= 120 km − 40 km

= 80 km

Thus, average speed of the car

=

= km/h

= 40 km/h