Question

the length of a rectangle is 20 centimetres more than its breadth if the perimeter is 100 centimetre find the dimension of the rectangle

Answer 1

According to the question ;
l = 20 + b -----------(1)

Perimeter = 2(l+b)

100 = 2(l+b) --------(2)

100 = 2 [(20+b)+b]
100/2 = 20+2b
50-20 = 2b
2b = 30
b = 15

l = 20+b
l = 20+15
l = 35
----------------------------
Hence the length and breadth of the rectangle if 35cm & 15cm.

Answer 2

Let the breadth of the rectangle be x and length of the rectangle be x+20.
Perimeter =2*(l+b)
100=2*(x+x+20)
50=2x+20
2x=30
x=15 cm
Dimensions of the rectangle = 15 cm & 15+20=35 cm.