Two boys A and B are at two diametrically opposite points on a circle. At one
instant the two start running on the circle; A anticlockwise with constant speed v
and B clockwise with constant speed 2v. In 2 minutes, they pass each other for
the first time. How much later will they pass each other for the second time?
1. 1 minute
2. 2 minutes
3. 3 minutes
4. 4 minutes