Question

A train covers the first half of the distance between
two stations at a speed of 40 km/h and the other
half at 60 km/h. Then its average speed is :-
(1) 50 km/h
(2) 48 km/h
(3) 52 km/h
(4) 100 km/h​

Answer 1

Answer: 48km/h

Explanation:

Let total distance covered = 2x

Distance = speed × time

Distance covered in first half= x

Time taken t1 = x/40

Distance covered in second half = x

Time taken t2 = x/60

Total time taken = t1+t2 = x/40 + x/60

(3x+2x)/120 = 5x/120 = x/24

Average Speed = Total distance covered/ Total time taken

= 2x/(x/24)

=2×24 = 48km/h