Calculation: Let the length of the other train be ‘x’ m Since The two trains are running in opposite directions So, Their relative speed is the sum of their individual speeds ⇒ Relative speed = 84 + 78 = 162 km/hr =162×
5
18
=45 m/sec Now, Time taken to cross each other = (Sum of their lengths) / (Their relative speed) ⇒7.2=
(170+x)
45
⇒ 170 + x = 324 ⇒ x = 324 - 170 = 154 m ∴ The other train is 170 – 154 = 16 m smaller than the first train.