Two trains, 230 m and 90 m long, are running on parallel tracks in opposite directions at 54 km/h and 18 km/h. How long will they take to cross each other completely?

💡 Solution & Explanation

In opposite directions, the speeds add: 54 + 18 = 72 km/h = 72 × 5/18 = 20 m/s. To cross completely, they cover both lengths: 230 + 90 = 320 m. Time = 320 ÷ 20 = 16 seconds. In the same direction the speeds would subtract instead.