A metro 140 m long overtook a person who was moving at the speed of 8 kmph in the same direction of the metro and crossed him in 15 seconds. Again, the metro overtook a second man who is also moving in the same direction of the metro in 21 seconds. At what speed (in kmph) was the second man moving?
1
20.3
2
17.6
3
6.8
4
15.6
5
11.6