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A train x running at 74 km/h crosses another train y running at 52 km/h in the opposite direction in 12 seconds. If the length of y is two-thirds that of x, then what is the length of x (in m)?1. 2002. 1683. 2104. 252 |
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Answer» Correct Answer - Option 4 : 252 Given: A train x running at 74 km/h crosses another train y running at 52 km/h in the opposite direction in 12 seconds. The length of y is two-thirds that of x. Concept Used: When two trains crossing each other, their relative speed will be the sum of their speed. 1 km/h = (5/18) m/s Distance = Time × speed Calculation: Relative speed (74 + 52) = 126 km/h ⇒ 126 × (5/18) ⇒ 35 m/s Time taken to cross each other 12 second Total distance covered (12 × 35) = 420 m The length of y is two-thirds that of x Let, the length of the train x is a meter Accordingly, (a + (2a/3) = 420 ⇒ a = 420 × (3/5) ⇒ a = 252 ∴ The length of the train X is 252 m |
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