Question

The length of a rectangle is twice its breadth ,the perimeter is 42 cm what is the length and the breadth?

Answer 1

Perimeter = p
length = l
breadth = b
l = 2b
p = 2l + 2b
p = 4b = 2b
p = 6b
42 = 6b
b = 42/6
b = 7
l = 2 x 7
l = 14