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A train leaves Delhi at 5 a.m. and reaches Kanpur at 10 a.m. another train leaves Kanpur at 7 a.m. and reaches Delhi at 2 p.m. at what time do the two trains meet ?
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- 8:45 a.m.
- 3:45 p.m.
- 6:45 a.m.
- data inadequate
Correct Option: A
Let the distance between Delhi and Kanpur be y km .
Suppose the train leaving from Delhi is A and the train leaving from Kanpur B
A's speed = y/ (10 a.m - 5 a.m) = y/5 km/hr.
B's Speed = y/ (2 p.m - 7 a.m) = y/7 km/hr.
Since B starts two hours later than A, the distance already covered by A at the start of B = 2y/5 km.
Remaining distance = y- 2y/5 = 3y/5 km.
Relative speed of approach of two trains = (y/5 + y/7)
= 12y/35 km/hr.
Time taken to cover the remaining distance by both trains = (3y / 5) / (12y / 35)
= (3/5) x (35/12) = 7/4 hrs.
= 1 hr. 45 min.
∴ The two train will meet at (7 a.m + 1hr.45 min)
= 8.45 a.m
