Question

A boy runs around a rectangular field, the length of which is 35 meters. If the breadth is 20 meters then how much distance will he run?

Answer 1

Hint: As given that a boy runs around a rectangular field and the length and breadth of rectangular field is given in the question. The distance covered by the boy is equal to the perimeter of the rectangular field. So, we calculate the perimeter of the rectangular field by using the formula
$\begin{align}
  & \text{Perimeter}=2\left( l+b \right), \\
 & \text{where, }l=length \\
 & b=breadth \\
\end{align}$

Complete step-by-step solution:
We have been given that a boy runs around a rectangular field and the length of the rectangular field is $35m$ and breadth is $20m$.
The rectangular field is shown in the figure below:

We have to find the distance covered by the boy.
Now, the boy runs around the rectangular field, so the distance covered by the boy is equal to the perimeter of the rectangular field.
We know that perimeter of the rectangle is given by
$\begin{align}
  & \text{Perimeter}=2\left( l+b \right) \\
 & \text{where, }l=length \\
 & b=breadth \\
\end{align}$
We have
$\begin{align}
  & l=35 \\
 & b=20 \\
\end{align}$
Now, substituting the values in the formula and simplifying further, we get
$\begin{align}
  & \text{Perimeter}=2\left( 35+20 \right) \\
 & \text{Perimeter}=2\left( 55 \right) \\
 & \text{Perimeter}=110m \\
\end{align}$
We have the perimeter of the rectangle equal to $110m$.
So, the distance covered by the boy is $110m$.

Note: Perimeter of the rectangle is the total distance covered by its boundaries in two dimensional shapes. In this question given that the boy runs along boundaries so we calculate the perimeter instead of calculating the area of the rectangle. We can also find the perimeter of the rectangle by adding all four sides of the rectangle.