Time Distance

Question

Two trains A and B start simultaneously in the opposite direction from two points A and B and arrive at their destination 9 and 4 hrs respectively after their meeting each other. At what rate does the second train B travel if the fist travel at 80 kmph.

 

Answer 1

Speed of A/Speed of B= square root(time of B/time of A)

80/x=square root(4/9)

80/x=2/3

x=120km/h

Comments

@Learner_jai can you give brief overview how can i derive that relation