Multiple choice

A train $108$ m long moving at a speed of $50$ km/hr crosses a train $112$ m long coming from the opposite direction in $6$ seconds. What is the speed of the second train ?

  1. $78$ km/hr
  2. $82$ km/hr
  3. $84$ km/hr
  4. $90$ km/hr
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total distance = 108 + 112 = 220 m. Time = 6 s. Relative speed = 220/6 m/s = 110/3 m/s. Convert to km/hr: (110/3) * (18/5) = 132 km/hr. Since they are moving in opposite directions, relative speed = v1 + v2. 132 = 50 + v2, so v2 = 82 km/hr.

AI explanation

The total distance covered is the sum of the lengths of both trains, 108 + 112 = 220 m. If the second train's speed is v km/hr, the relative speed in opposite directions is (50 + v) * (5/18) m/s. Using distance equals speed times time, we get 220 / 6 = (50 + v) * (5/18), which solves to v = 82 km/hr.

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