Question

The perimeter of a rectangle is 60cm.if it's area is 200 cm^2 .find its length and breadth in centimeter

Answer 1

Let
Lenght = x cm
Breadth = ycm

Perimeter = 60
2(x+y)= 60

x+y =30 ..(1)

Area = 200
x*y = 200
x=200/y

Put in (1)
200/y + y =30

(200 + y^2)/y = 30

(200 + y^2) = 30y

y^2 -20y -10y + 200 =0

y(y-20) -10(y-20) = 0

(y-10)*(y-20)=0

>> y=10,20
From (1)
if y = 10 >> x=30-10=20
if y=20 >> x=30-20=10 

Answer 2

l×b = 200 ---------- 1
2l+2b = 60
l + b =30
l = 30-b
put l = 30 - b in equation 1
(30- b) b = 200
b=20 , 10
l= 10 , 20