Two boats A and B start towards each other from two places , 108 km apart .Speed of the boa A and B in still water are 12 km /hr and 15 km /hr respectively . If A proceeds down and B up the stream , they will meet after .

Options

A. 4.5 hours
B. 4 hours
C. 5.4 hours
D. 6 hour

Answer

B