Arvind and Chetan started running simultaneously from the same point in the same direction on a circular track of length 210 m. If Arvind takes 180 seconds to complete one round, and Chetan takes 420 seconds to complete one round, after how much time will they meet for the first time at the starting point on the track?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 21 minutes.
Arvind's Speed = 210/180 = 7/6 m/s
Chetan's Speed = 210/420 = 1/2 m/s
LCM of 180 and 420 = 1260
1260 seconds = 21 minutes
The LCM (21 minutes) is the time it will take for both Arvind and Chetan to meet at the starting point again.
Therefore, they will meet for the first time at the starting point on the track after 21 minutes.