Two persons started running on a circular track at a speed of 20 m/s and 30 m/s in opposite directions. If the circumference of the circular track is 100 m, find at how many distinct points they will cross each other.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 5.
Given that
Two persons started running on a circular track at a speed of 20 m/s and 30 m/s in opposite directions
The circumference of the circular track is 100 m,
According to the question
The relative speed of both persons = 30 + 20 = 50 m/s
They meet at the starting point again after = LCM (100/20, 100/30) = LCM (100,100)/HCF (20, 30) = 100/10 = 10 sec
The time taken to meet at any point of circular track = circular track/relative speed = 100/50 = 2 sec
Hence, the distinct points on which they will cross each other = 10/2 = 5