Two trains, A and B started travelling towards each other at the same time, from places P to Q and Q to P, respectively. After crossing each other, A and B took 9hours and 16hours to reach Q and P, respectively. If the speed of A was 56km/h, then what was the speed (in km/h) of B?

When two objects start from two points at the same time moving towards each other and after crossing each other they take time t
1
​
and t
2
​
to reach their respective destinations, the relation between their speeds is given by:

Speed of B
Speed of A
​
=
t
1
​

t
2
​

​


​

Given:

Speed of A (s
A
​
) = 56km/h

Time taken by A after crossing (t
1
​
) = 9hours

Time taken by B after crossing (t
2
​
) = 16hours

Let the speed of B be s
B
​
.

s
B
​

56
​
=
9
16
​


​

s
B
​

56
​
=
3
4
​

4×s
B
​
=56×3
s
B
​
=
4
56×3
​
=14×3=42km/h