Question

The area of rectangle is 12 sq mts and its length is 3 times that of its breadth what is the perimeter of rectangle

Answer 1

16 metres......
let's assume the breadth to be x
area= l×b
i.e 3x × x.
3x^2 =12
x = 2

and perimeter = 2(l+b)
2(6+2)....
answer is 16

Answer 2

Area = 12 m^2
Length,L= 3*B
Area = L*B
12 = 3*B*B
B*B= 12/3 = 4 
B = root(4) = 2m
B = 2 m, L= 2*B= 6 m
Perimeter= 2*[L+B] = 2*[2+6] = 16 m