Question

Please help me guys.BEST ANSWER WILL BE BRAINLIEST. "The perimeter of a rectangular plot is 120m. The lenght of the plot is decreased by 5m and breadth is increased by 5m,then the area is increased by 75 sq.m .Find the dimensions of the plot."​

Answer 1

Here's what u need:

Let the length of the plot be x m.

Then, 2(l+b)=120

           x+b=60

           b=60-x  (eqn 1)

   So, area of the plot = x*(60-x) = 60x- x²

 Hence, area of plot = 60x- x²   (eqn 2)

Also according to question,

   length is decreased by 5 i.e. (x-5) m

  and breadth is increased by 5 i.e. (60-x+5) m = (65-x) m (from eqn 1)

  area = (x-5)(65-x)

Hence,

  60x- x²+75=(x-5)(65-x)

  -x²+60x+75 = 65x-325-x²+5x

   75 = -x²+70x-325+x²-60x

  75+325 = 10x

  400 = 10x

  40 = x

 So, length of the plot = 40m

So, breadth of the plot = (60 - 40)m = 20m.

Hope it helps!!