Answer:the length and width of the rectangle are 12 and 8 respectively
Explanation:
Step 1
The perimeter of a rectangle is 2l + 2w where l= length and w= width giving us that
2l+2w=P
2l + 2w = 40
2(l+w)= 40
l +w = 20
Also we were given The difference between the length and width of a rectangle is 4 units giving us that
l-w= 4
Here our systems of equation to solve the problem
l-w= 4----- Equation 1
l +w = 20-----Equation 2
Step 2
I-w=4---- Equation 1
l +w = 20---Equation 2
Adding equation 1 and 2
I-w=4
+l +w = 20
2l =24
l=24/2
=l=12
To find w, we put the value of l=12 into equation 1
I-w=4
12-w= 4
w= 12-4
w=8
Therefore the length and width of the rectangle are 12 and 8 respectively