In a circular race of 1500 m, A and B start running simulataneously at a speed of 27 km/hr and 45 km/hr from the same point and the same time. After how much time will they meet at the starting point for the first time if they are running in the opposite direction?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 10 min .
Track length = 1500 m
Speed of A = 27 km/hr = 27 × 5/18 = 7.5 m/s
Speed of B = 45 km/hr = 45 × 5/18 = 12.5 m/s
Time for A to complete one lap = 1500 ÷ 7.5 = 200 s
Time for B to complete one lap = 1500 ÷ 12.5 = 120 s
LCM of 200 and 120 = 600 s
600 s = 10 minutes