Subject :IMO Class : Class 10
X takes 3 hours more than Y to walk 30 km. But, if X doubles his pace,
he is ahead of Y by 
hour.
Find their speed of walking.
A7 km/h, 4 km/h
B10/3 km/h, 5 km/h
C2 km/h, 3/2 km/h
D3 km/h, 7 km/h