Question

if a trains runs at 40 kmph it reaches it's destination late by 11 minutes. But if it runs at 50 kmph it is late by 5 minutes only. Find the distance covered by the train. The answer should be 20 km.

Answer 1

Let the distance travelled by the train be x. Also supposeBhr time taken by the train when it never gets late is t.
In the 1st case the train gets late by 11 min i.e., 11/60h.
t+(11/60)= x/40
In the second case the train gets late by 5 min i.e., 5/60 h.
t+5=x/50
Now subtract eq2 from eq1, we find
(11/60)-(5/60) = x/200
On solving we get x=20 km