Question

it is possible to design a rectangular park of perimeter 80 m and area 400 m ? so, find its length and bredth.

Answer 1

Ok so perimeter is 2(l+b) = 80
l + b = 40

l x b = 400

b = 400/l

l + 400/l = 40

Here we get a quadratic equation

$l {}^{2} - 40l + 400 = 0$
on solving we get l = 20

so 20 x b = 400
b = 20

Note : as we have l = b = 20 so it is a square