To travel 600 km, train A takes 2 hours more than train B. If the speed of train B is doubled, then, train B takes 4 hours less than train A. The speed (in km/hr) of train A and train B, respectively?
1
(60, 40)
2
(100, 150)
3
(50, 60)
4
(40, 50)
5
None of these