Question

A car travels a distance of 45 kms at the speed of 15 kmph. It covers the next 50 kms of its journey at the speed of 25 kmph and the last 25 kms of its journey at the speed of 10 kmph. What is the average speed of the car?

(a) 40 kmph (b) 24 kmph (c) 15 kmph (d) 18 kmph (e) of these

Answer 1

(e) Time taken to cover a distance of 45 kms

=45/15 = 3 hours

Time taken to cover a distance of 50 kms

=50/25 = 2 hours

Time taken to cover distance of 25 kms

=25/10 = 2.5 hours

Total distance = (45 + 50 + 25) kms = 120 kms
Total time = (3 + 2 + 2.5) hours = 7.5 hours

Required average speed =120/7.5=16 kmph