The speed ratio of a and B is known to be 3:4. A starts 15 minutes earlier than B. after 1 hour and 45 minutes, a encounters B. at this time, a walks 6 kilometers less than B. how about the speed of a and B's car and the distance between AB and B?

The speed ratio of a and B is known to be 3:4. A starts 15 minutes earlier than B. after 1 hour and 45 minutes, a encounters B. at this time, a walks 6 kilometers less than B. how about the speed of a and B's car and the distance between AB and B?

Suppose that the speed of a is 3x km / h and that of B is 4x km / h. when meeting, the distance of a is 6x km and that of B is 7x km,
7x-6x = 6, x = 6
The speed of a is 18 km / h, and that of B is 24 km / h;
The distance between a and B is: 6x + 7x = 13X = 78 (km)