Arectangular lot whose perimeter is 380 ft is fenced along three sides. an expensive fencing along the lot's length cost $ 25 per foot. an inexpensive fencing along the two side widths costs only $ 5 per foot. the total cost of the fencing along the three sides comes to $ 3625. what are the lot's dimensions?

We have two widths of the same length plus one length

Let the width be  and the length be 

Perimeter = 2×width + 2×length

 
(equation 1)

The cost is $5 per foot on the width and $25 per foot on the length
Total cost = (5 × 2 × width) + (25 × length)
(equation 2)

We have two variables that we need to solve, so we will need to use the simultaneous equations method (either elimination or substitution)

Since equation 1 is given , we can rearrange the equation to make  the subject



then substitute this into equation 2










Substitute w = 75 back into 190 = w + l

190 = 75 + l
l = 190 - 75
l = 115

Length = 115 feet
Width = 75 feet