Question 269703
A rectangular lot whose perimeter is 220 feet is fenced along three sides.  An expensive fencing along the lot's length  costs $20 per foot, and an inexpensive fencing along the two side widths costs only $8 per foot.  The total cost of the fencing along the three sides comes to $2040.  What are the lot's dimensions? 

Let the length be x

the sum of two lengths will be 2x

The two widths together will be 220-2x

the cost for one length will be $20 * x

and the cost for two widths will be $8* (220-x)

The total cost is $2040

So, 20x+8(220-x)= 2040

20x+1760-8x=2040

12x=2040-1760

12x=280

x= 280/12

x= 23.33  feet  which is the length

Substitute the value of x in the term 220-2x 

220-2*23.33

220-46.66= 173.34 which is sum of two widths.

dividing by 2 we get 86.67 feet which is measurement of one width.


23.33 feet  is the length
86.67 feet which is the width.