The ratio of the length of a school ground to its width is `5 : 2`. If the width is 40 m, then the length is:

Options

A. 200 m
B. 100 m
C. 50 m
D. 80 m

Answer

To find the length of the school ground given the ratio of length to width, we can follow these steps:

### Step 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 units of length, there are 2 units of width.

### Step 2: Set Up the Ratio
Let the length be represented as \( L \) and the width as \( W \). According to the ratio, we can express this relationship as:
\[ \frac{L}{W} = \frac{5}{2} \]

### Step 3: Substitute the Width
We know that the width \( W \) is 40 m. We can substitute this value into the ratio:
\[ \frac{L}{40} = \frac{5}{2} \]

### Step 4: Cross-Multiply
To solve for \( L \), we can cross-multiply:
\[ L \cdot 2 = 5 \cdot 40 \]

### Step 5: Calculate
Now, calculate the right side:
\[ L \cdot 2 = 200 \]

### Step 6: Divide to Find Length
Now, divide both sides by 2 to find \( L \):
\[ L = \frac{200}{2} = 100 \]

### Step 7: Conclusion
Thus, the length of the school ground is 100 meters.