
Shortcut Trick
Speed of the 1st train = 442 ÷ 13 = 34 m/s
Total distance when crossing each other = 442 + 442 = 884 m
Relative speed (opposite direction) = 884 ÷ 17 = 52 m/s
Speed of the 2nd train = Relative speed − Speed of 1st train
⇒ 52 − 34 = 18 m/s
∴ The correct answer is 18 m/s.

Alternate Method
Scenario 1: Crossing an Electric Pole
Pole
Train 1 (442m)
Cross Time = 13s | Speed = S1
Scenario 2: Crossing Train in Opposite Direction
Train 1 (442m)
Train 2 (442m)
Relative Speed = S1 + S2 | Total Distance = 884m | Time = 17s
Given:
Length of the 1st train (L1) = 442 m
Length of the 2nd train (L2) = 442 m
Time to cross the electric pole (t1) = 13 s
Time to cross the second train (t2) = 17 s
Formula Used:
Speed = Distance ÷ Time
Relative Speed (Opposite Directions) = S1 + S2
Calculations:
⇒ Speed of 1st train (S1) = L1 ÷ t1
⇒ S1 = 442 ÷ 13 = 34 m/s
When the two trains cross each other in opposite directions:
⇒ Total Distance = L1 + L2 = 442 + 442 = 884 m
⇒ Relative Speed = Total Distance ÷ t2
⇒ S1 + S2 = 884 ÷ 17
⇒ 34 + S2 = 52
⇒ S2 = 52 − 34
⇒ S2 = 18 m/s
∴ The correct answer is 18 m/s.

Additional Information
Relative Speed in Opposite Directions
When two objects move towards each other, their relative speed is the sum of their individual speeds (S1 + S2) because they are covering the total distance together.
Relative Speed in Same Direction
When two objects move in the same direction, the faster object covers extra distance to overtake the slower one, making their relative speed the difference of their speeds (S1 − S2).
Train Crossing a Point Object
When a train crosses a stationary pole, standing man, or a tree, the total distance traveled is simply equal to the length of the train itself (Distance = L).
Train Crossing a Lengthy Object
When a train crosses a platform, a bridge, or another train, the total distance covered to clear it completely is the sum of their lengths (Distance = L1 + L2).