SOLUTION: The length or a rectangle is 15cm longer than its width. When its width is increased by 3cm and its length is decreased by 5cm, the area of the new rectangle is 20cm² bigger than t

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: The length or a rectangle is 15cm longer than its width. When its width is increased by 3cm and its length is decreased by 5cm, the area of the new rectangle is 20cm² bigger than t      Log On


   

Question 1066237: The length or a rectangle is 15cm longer than its width. When its width is increased by 3cm and its length is decreased by 5cm, the area of the new rectangle is 20cm² bigger than the original rectangle.
Find the original dimension of the new rectangle.
Answer by jorel1380(3719) About Me  (Show Source):
You can put this solution on YOUR website!
Let w be the width of the rectangle. Then the length would be w+15. So:
(w+3)(w+15-5)-w(w+15)=20
w²+13w+30-w²-15w=20
30-2w=20
w=5
The original rectangle was 5 x 20 cms., the new rectangle is 8 x 15 cms. ☺☺☺☺