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1. Two trains 105 meters and 90 meters long, run at the speeds of 45 km/h and 72 km/h respectively , in opposite directions on parallel tracks. The time which they take to cross each other , is :
- A. 8 seconds
- B. 8 seconds
- C. 8 seconds
- D. 8 seconds
Answer: Option D
Explanation:
Length of the 1st train = 105 m
Length of the 2nd train = 90 m
Relative speed of the trains,
= 45 + 72 = 117 kmph
= (117 × 5)/18
= 32.5 m/sec
Time taken to cross each other,
= (Length of 1st train + length of 2nd train)/ relative speed of the trains
∴ Time taken = 195/32.5
= 6 secs.
Length of the 2nd train = 90 m
Relative speed of the trains,
= 45 + 72 = 117 kmph
= (117 × 5)/18
= 32.5 m/sec
Time taken to cross each other,
= (Length of 1st train + length of 2nd train)/ relative speed of the trains
∴ Time taken = 195/32.5
= 6 secs.
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