two cars p and q start at the same time from a and b which are 120 km apart - Interview Questions

two cars p and q start at the same time from a and b which are 120 km apart

A and B are two cars travelling to a destination which is 360 kilometres away. A takes 4 hours to reach the destination. How much time will it take B to reach the destination if the speeds of A and B are in the ratio 9: 12 ?

Answer : D. 3 hrs