car A and car B are travelling on two perpendicular roads towards city C with equal speeds. car A starts from a distance of 100 km ar 11 a.m while car B starts from a distance of 70 km at 12 noon. At 2p.m the two cars are 50 km apart. What is the speed with which they are travelling?
a)25 kmph b)20 kmph c)30 kmph d)15 kmph