Question

The length of a is 3 times its width if the perimeter is 400ft what is the length and width of the fence

Answer 1

width is x
length is 3x

(Don't forget that perimeter has 2 sides of width and 2 sides of length)

so perimeter is 400 = 2(x)+2(3x)
400 = 2x+6x
400 = 8x
so x = 50
then the length of the fence is 50ft
the width of the fence is 150ft