A and B run a 12 km race on a circular track of length 1200 m. They complete on around in 300 seconds and 400 seconds, respectively. After how much time from the start will the faster person meet the slower person for the last time?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1i.e. 2400 seconds
Given that
A and B run a 12 km race on a circular track of length 1200 m.
⇒Total rounds of circular track = 12000/1200 = 10 rounds
⇒Time taken to complete one round of 1200 m by A = 300 sec
⇒Time taken to complete one round of 1200 m by B = 400 sec
Now,
⇒Time taken to complete 10 rounds of 1200 m by A = 300 * 10 = 3000 sec
When A and B both start running
⇒The first meet will take place LCM (300, 400) = 1200 sec
⇒The second meet will take place = 1200 * 2 = 2400 sec
⇒The third meet will take place = 1200 * 3 = 3600 sec which is not possible because A complete race in 3000 sec.
Hence, time will not be greater than 3000 sec
Thus, the faster person will meet the slower person for the last time = 2400 sec.