The ratio of the length of a school ground to its width is 5:2. Find its length, if the width is 40 metres

Answer

To solve the problem step by step, we can follow these instructions:

1. **Understand the Ratio**: The ratio of the length (L) to the width (W) of the school ground is given as 5:2. This means that for every 5 parts of length, there are 2 parts of width.

2. **Express Length and Width in Terms of a Variable**:
- Let the length be represented as \( L = 5x \)
- Let the width be represented as \( W = 2x \)

3. **Use the Given Width to Find x**:
- We know that the width \( W \) is 40 meters. So, we can set up the equation:
\[ 2x = 40 \]

4. **Solve for x**:
- To find \( x \), divide both sides of the equation by 2:
\[ x = \frac{40}{2} = 20 \]

5. **Calculate the Length**:
- Now that we have \( x \), we can find the length using the expression for length:
\[ L = 5x = 5 \times 20 = 100 \text{ meters} \]

6. **Conclusion**:
- Therefore, the length of the school ground is 100 meters.