Area Path
1. **Problem Statement:**
We have a rectangular field with perimeter 70 m. Its length is 15 m longer than its breadth. The field is surrounded by a concrete path with widths 5 m (top) and 2.5 m (left). We need to find the area of the path.
2. **Define variables:**
Let the breadth be $b$ meters.
Then the length is $l = b + 15$ meters.
3. **Use perimeter formula:**
Perimeter $P$ of a rectangle is given by:
$$P = 2(l + b)$$
Given $P = 70$, substitute:
$$70 = 2(b + 15 + b) = 2(2b + 15) = 4b + 30$$
4. **Solve for breadth $b$:**
$$4b + 30 = 70$$
$$4b = 70 - 30 = 40$$
$$b = \frac{40}{4} = 10$$ meters
5. **Find length $l$:**
$$l = b + 15 = 10 + 15 = 25$$ meters
6. **Dimensions of the field:**
Length = 25 m, Breadth = 10 m
7. **Dimensions including the path:**
The path adds 5 m on top and 2.5 m on left side. Assuming the path surrounds the field on all sides with these widths, the total length and breadth including the path are:
- Total length = field length + 2 * path width on length sides = $25 + 2 \times 5 = 25 + 10 = 35$ m
- Total breadth = field breadth + 2 * path width on breadth sides = $10 + 2 \times 2.5 = 10 + 5 = 15$ m
8. **Calculate areas:**
- Area of field = $l \times b = 25 \times 10 = 250$ m$^2$
- Area of field + path = total length $\times$ total breadth = $35 \times 15 = 525$ m$^2$
9. **Area of the path:**
$$\text{Area of path} = \text{Area of field + path} - \text{Area of field} = 525 - 250 = 275$$ m$^2$
**Final answer:**
The area of the concrete path is **275 square meters**.