A and B are participants in a 1,800 m circular race. A is running at a speed of 24 km/h and B is running at a speed of 15 km/h. If both start from the same point and at the same time and run in the same direction, find the time when they will meet again. (up to two decimal points)

First, let's convert the speeds from km/h to m/s:
Speed of A=24×
18
5
​
=
3
20
​
 m/s
Speed of B=15×
18
5
​
=
6
25
​
 m/s
Since they are running in the same direction, their relative speed is:

Relative Speed=Speed of A−Speed of B=
3
20
​
−
6
25
​
=
6
40−25
​
=
6
15
​
=
2
5
​
 m/s
The time taken to meet for the first time on the circular track is:

Time=
Relative Speed
Length of circular track
​

Time=
2
5
​

1800
​
=
5
1800×2
​
=360×2=720 seconds