Question

the perimeter of a rectangle is 360m. if its length is decresed by 20 % and its breadth is increased by 25% we get the same perimeter . find the dimention of the rectangle

Answer 1

The original dimensions of rectangle are 100 m and 80 m

1) Given the perimeter of rectangle is 360 m

2) Let the original length be x and original breadth be y m.

3) The perimeter of rectangle would be 2(x+y) =360 or x+y = 180 m

4) Decreasing the length by 20% and increasing the breadth by 25%

5) The new length would be 4x/5 and new breadth would be 5y/4

6) The new perimeter would be 2( 4x/5 + 3y/4 ) = 360  or 4x/5 + 5y/4 = 180 or 16x + 25y = 3600

7) Solving these two equations in two variables gives x = 100 m and y = 80 m