Question
A train passes a stationary pole in 18 seconds and
passes a bridge of length 540 metres in 45 seconds. What is the speed of the train in km/h?Solution
ATQ, Let speed of train = v m/s Let length of train = L metres From pole: L = v × 18 …(1) From bridge (length = 540 m): Distance covered = L + 540 = v × 45 …(2) Substitute L from (1) into (2): v × 18 + 540 = v × 45 540 = 45v − 18v = 27v v = 540 / 27 = 20 m/s Convert m/s to km/h: 20 × (18/5) = 72 km/h So, speed of the train = 72 km/h.
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