In a circular race of 1100 m, P and Q start from the same point, at the same time, and at speeds of 36 km/h and 63 km/h, respectively. When will they meet again for the first time on the track if they are running in opposite directions?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1, i.e., 40 s.
Convert speeds to m/min:
36 km/h = 36 × 1000 ÷ 60 = 600 m/min
63 km/h = 63 × 1000 ÷ 60 = 1050 m/min
Since they run in opposite directions, relative speed = 600 + 1050 = 1650 m/min
Time = Distance ÷ Relative speed = 1100 ÷ 1650 = 2/3 min
Time = 40 seconds