A and B set out at the same time from a and B which are 180 km apart. A rides a bicycle and B drives a car along the same route. It is known that a's speed is 15 km / h and B's speed is 45 km / h How many hours did they meet? How many hours did B arrive at a?

A and B set out at the same time from a and B which are 180 km apart. A rides a bicycle and B drives a car along the same route. It is known that a's speed is 15 km / h and B's speed is 45 km / h How many hours did they meet? How many hours did B arrive at a?

(1) Let's meet in X hours
That is: 15x + 45x = 180
X=3(h)
A: they met in three hours
(2) First calculate the distance left after meeting: 180-45 * 3 = 45 (km)
45|45=1(h)
A: one hour after the meeting, B arrived at a