In a circular race of 950 m length, A and B start with speeds of 18 km/h and 36 km/h, respectively, in the same direction, at the same time, from the same point. After how many seconds will they meet for the first time at the starting point?
- A90
- B195
- C190
- D95
Solution & Step-by-step Explanation
First convert speeds from km/h to m/s:
Speed of A = 18×
18
5
=5m/s
Speed of B = 36×
18
5
=10m/s
Time taken by A to complete one full round =
5
950
=190 seconds
Time taken by B to complete one full round =
10
950
=95 seconds
They will meet at the starting point at a time which is the LCM of their individual times:
LCM(190,95)=190 seconds
Speed of A = 18×
18
5
=5m/s
Speed of B = 36×
18
5
=10m/s
Time taken by A to complete one full round =
5
950
=190 seconds
Time taken by B to complete one full round =
10
950
=95 seconds
They will meet at the starting point at a time which is the LCM of their individual times:
LCM(190,95)=190 seconds