A goods train runs at a speed of 72 km per hour and crosses a 250 m long platform in 26 seconds. What is the length of the goods train?

Let length of the goods train is x m. 

Speed of the train= 72 km/hr.

$=72\times \frac{5}{18}=20\mathrm{m}/\sec$.

According to the question,

$\begin{array}{l}\frac{\mathrm{x}+250}{20}=26\\ \mathrm{x}+250=520\\ \mathrm{x}=270\mathrm{m}.\end{array}$

So, length of the goods train is 270 m.