Multiple choice general knowledge math & puzzles

Two trains A and B which run at constant speed are running on parallel tracks.After crossing eact other they take 36minutes and 144minutes to reach their destinations which is to exchange their positions.What is the ratio of their speeds of A and B.

  1. 0.5

  2. 2

  3. 2.4

  4. 4.8

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The ratio of speeds of two objects starting from A and B and meeting at a point, then reaching their destinations in times t1 and t2, is given by SpeedA / SpeedB = sqrt(t2 / t1). Here, sqrt(144 / 36) = sqrt(4) = 2.