Question

A train X starts from New Delhi at 4 pm and reaches Ghaziabad at 5 pm. While another train Y starts from Ghaziabad at 4 pm and reaches New Delhi at 5 : 30 pm. At what time will the two trains cross each other?

Answer 1

Let Delhi – Ghaziabad distance be a km. Then, 

Speed of train X = a km/hr 

Speed of train Y = \(\frac{a}{\frac{3}{2}}\) km/hr = \(\frac{2a}{3}\) km/hr 

Suppose they meet after b hours, then \(ab + \frac{2ab}{3} =a ⇒\frac{5b}{3}=1⇒b=\frac35\) hrs = 36 minutes

∴ They meet at 4 : 36 pm.