A train of length 240 m crosses a platform in 20 s. If the speed of the train is 72 km/h, then find the length of the platform.

Explanation

To solve the problem step by step, we need to find the length of the platform given the length of the train and the time it takes to cross the platform.

**Step 1: Convert the speed of the train from km/h to m/s.**
- The speed given is 72 km/h.
- To convert km/h to m/s, we use the conversion factor \( \frac{5}{18} \).

\[
\text{Speed in m/s} = 72 \times \frac{5}{18} = 20 \text{ m/s}
...