Train P starts from A at 10 am and runs at a constant speed of 60 kmph on a straight track and reaches B covering a distance of 360 km. Train Q starts from B at 11 am and runs towards A at a constant speed. It crosses train P at a distance of 120 km from B. What is the speed of train Q?

A

40 kmph

B

30 kmph

C

50 kmph

D

60 kmph