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SSC Selection Post 2022 PYQ — Question 60

SSC Selection Post - Higher Secondary Level 2022 - 15 March 2022 - Shift 2 • Quantitative Aptitude • Q60

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A train passes two bridges 400 m and 295 m long in 75 seconds and 60 seconds, respectively. How much time (in seconds) will the train take to cross another train of length 325 m running on parallel tracks at the speed of 97.2 km/h in same direction?

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Correct answer: D

Explanation

The correct answer is Option 4 i.e. 221222{{1} \over 2}

(L + 400)/75 = (L + 295)/60 (L = length of train ) 

60(L + 400) = 75(L + 295)

15L = 1875 ⇒ L = 125

Speed of train: S = (125 + 400)/75 = 525/75 = 7 m/s

Speed of second train: 97.2 km/h = (97.2 × 1000)/3600 = 27 m/s

Relative speed (same direction): 27 - 7 = 20 m/s

Total length to cross = 125 + 325 = 450 m

Time = 450/20 = 22.5 seconds