college question

Question

a rectangular lot whose perimeter is 250 ft is fenced along three sides. an expensive fencing along the lot's length costs 30 dollars per foot. An inexpensive fencing along the two side widths costs only 6 dollars per foot, the total cost of all three sides is 2940 dollars, what are the lots dimensions

Answer 1

Let x = length of expensive fencing

 

     y = length of each of the other 2 sides

 

Then, 2x + 2y = 250, so y = 125 - x

 

         cost of fence = 30x + 6(2y) = 2940

 

                                30x + 12(125-x) = 2940

 

                                                  18x = 1440

 

                                                     x = 80 ft     y = 125-x = 45 ft