it Raju covers 1760 m when he runs around a rectangular ground 4 times, what is the length and breadth of the ground given that the length is 20 m more than the breadth

Dear Student,

Let the breadth of the rectangular ground be x.
Then, length $=\left(x+20\right)$
$$\begin{gathered} Perimeter =2\times \left(length+breadth\right) \\ =2\left(x+20+x\right) \\ =2\left(2x+20\right) \end{gathered}$$
Since, 4 rounds of the ground is 1760 m.
​$$\begin{gathered} \Rightarrow 4\times Perimeter=1760 \\ \Rightarrow 4\times 2\left(2x+20\right)=1760 \\ \Rightarrow 8\left(2x+20\right)=1760 \\ \Rightarrow 2x+20=\frac{1760}{8} \\ \Rightarrow 2x+20=220 \\ \Rightarrow 2x=220-20 \\ \Rightarrow 2x=200 \\ \Rightarrow x=\frac{200}{2} \\ \Rightarrow x=100 \end{gathered}$$
Thus, breadth of the ground is 100 m and length is 120 m.