Answer:
B) 80 m
Explanation:
Let W = width
Let L = length
perimeter of a rectangle = 2 x width + 2 x length = 2(W + L)
If the perimeter of a rectangle = 20 m
⇒ 2(W + L) = 20
If we multiply both its length and width by 4:
Width = 4W
Length = 4L
⇒ perimeter = 2(4W + 4L) = 8(W + L)
As 2(W + L) = 20
Then 8(W + L) = 4 x 2(W + L) = 4 x 20 = 80 m