Points A and B are 35 km apart on a highway. One car starts from A and the another one from B at the same time. If they travel in the same direction, they meet in 7 hours. But if they travel towards each other, they meet in one hour. The speed of the two cars are, respectively.
Explanation:
Let the speed of the car be x km/h and y km/h, respectively.
Their relative speeds when they are moving in same direction = (x – y) km/h.
Their relative speeds when they are in opposite directions = (x + y) km/h.
Now, 35x+y=1 or x + y = 35 …(1)
and 35x-y=7 or x – y = 5 …(2)
Solving (1) and (2), we have
x = 20 km/h and y = 15 km/h
Hence, option (c).
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