Answer:
The length and width of the deck will be 11 meters and 9 meters respectively.
Explanation:
The length of the rectangular deck is
meter and width is
meter.
The perimeter of the deck should be 40 meters. So, the first equation will be...
![2(l+w)= 40\\ \\ \Rightarrow l+w = 20 ..................................(1)](https://img.qammunity.org/2019/formulas/mathematics/high-school/h9emyore6nhpmbzct041qnd3uuylbd2ktf.png)
The difference between twice the length and twice the width should be 4 meters. So, the second equation will be....
![2l-2w= 4\\ \\ \Rightarrow l-w= 2 .................................(2)](https://img.qammunity.org/2019/formulas/mathematics/high-school/9x1dqh8uc2gh20ibbzlbzdtuqi0ojy2am4.png)
Adding equation (1) and (2), we will get.....
![(l+w)+(l-w)= 20+2\\ \\ 2l= 22\\ \\ l= (22)/(2)= 11](https://img.qammunity.org/2019/formulas/mathematics/high-school/hy8ytf7gd6l4spo2dw0pjtm6b9gk36q8y5.png)
Now plugging this
into equation (1), we will get....
![11+w= 20\\ \\ \Rightarrow w=20-11= 9](https://img.qammunity.org/2019/formulas/mathematics/high-school/7hbh00d3su2xej7lpdwd1rk977wirc8fke.png)
So, the length and width of the deck will be 11 meters and 9 meters respectively.