Two trains start simultaneously from two stations howrah and bandra, respectively towards each other on the same track. The distance between the two stations is 560 km and the speed of trains are 30 and 40km/h.
Simultaneously with the trains a sparrow sitting on the top of one of the train starts towards the other and reverses its direction on reaching the other train and so on . If the speed of sparrow is 80 km/h then the distance that the sparrow flies before being crushed between the train is:

Options

A. 70 km
B. 560 km
C. 640km
D. 650 km

Answer

C