A moving train 66 m long overtakes another train 88 m long moving in t

1.	A moving train 66 m long overtakes another train 88 m long moving in the same direction in 0.168 min. If the second train is moving at 30 km/hr, at what speed is the first train moving?(a) 85 km/hr (b) 50 km/hr (c) 55 km/hr (d) 25 km/hr
Answer» (a) 85 km/hr Let the speed of the first train be x km/hr. Then, Relative speed of first train w.r.t. second train = (\(x\) - 30) km/hr = (\(x\) - 30) x \(\frac{5}{18}\) m/sec Total distance travelled = (66 + 88) m = 154 m Time taken = 0.168 min = (0.168 × 60) sec = 10.08 sec ∴ (\(x\) - 30) x \(\frac{5}{18}\) x 10.08 = 154 ⇒ \(x\) - 30 = \(\frac{154\times18}{5\times10.08}\) ⇒ 55 ⇒ \(x\) = 85 km/hr.

A moving train 66 m long overtakes another train 88 m long moving in the same direction in 0.168 min. If the second train is moving at 30 km/hr, at what speed is the first train moving?(a) 85 km/hr (b) 50 km/hr (c) 55 km/hr (d) 25 km/hr

Answer»

(a) 85 km/hr

Let the speed of the first train be x km/hr. Then,

Relative speed of first train w.r.t. second train

= (\(x\) - 30) km/hr = (\(x\) - 30) x \(\frac{5}{18}\) m/sec

Total distance travelled = (66 + 88) m = 154 m

Time taken = 0.168 min = (0.168 × 60) sec = 10.08 sec

∴ (\(x\) - 30) x \(\frac{5}{18}\) x 10.08 = 154

⇒ \(x\) - 30 = \(\frac{154\times18}{5\times10.08}\) ⇒ 55

⇒ \(x\) = 85 km/hr.

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A moving train 66 m long overtakes another train 88 m long moving in the same direction in 0.168 min. If the second train is moving at 30 km/hr, at what speed is the first train moving?(a) 85 km/hr (b) 50 km/hr (c) 55 km/hr (d) 25 km/hr

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