if three runners A B and C start simultaneously from the same point and run around a circular track of length 500 metre in the same direction at the speed of 5 kilometre per hour to kilometre per hour and 15 km per hour respectively what is the time taken by them to meet for the first time
30 mints
60mints
Answers
Step-by-step explanation:
(i) A, B and C are running in the same direction. Let their speeds be S1, S2, S3 which are 5 m/sec, 8 m/sec and 3 m/sec respectively. The length of the track = 400 m.
The relative speed of A and B is = S1 - S2 = 8 - 5 = 3 m/sec.
The relative speed of B and C is = S2 - S3 = 8 - 3 = 5 m/sec.
We know that, when three people A, B and C are running in the same direction they will meet for the first time after L.C.M. (CS1−S2, CS2−S3) seconds.
i.e., L.C.M of (4003, 4005) = 400 seconds.
After 400 seconds, A would have run 2000 m, B would have run 3200 m and C would have run 1200 m.
(ii) A, B and C will meet at the starting point for the first time after LCM of (CS1, CS2, andCS3) seconds
i.e. L.C.M. of (4005, 4008, 4003) = 400 seconds
That is after 400 seconds, A, B and C will meet for the first time at the starting point