Question 262852
im having a hard time with this problem,please help! if the length of a rectangular parking lot is 20 meters less than twice its width,and the perimeter is 800 meters,find the length of the parking lot.

Let w be the width and l the length of the parking lot. Then we have:

1.) Perimeter = 2*w + 2*l = 800
2.) l = 2w - 20 

Let's rewrite these two equations:

1.) 2w + 2l = 800
2.) 2w - l  = 20

Subtracting equation 2.) from equation 1.) we have:

3*l = 780
l = 780/3 = 260

Calculate w from 2.:

2*w - 260 = 20
2w = 280
w = 140