The perimeter of a rectangle is 30 m. The length of the rectangle is 3 m less than twice the width. Find the length and width of the rectangle.

Question

The perimeter of a rectangle is 30 m. The length of the rectangle is 3 m less than twice the width. Find the length and width of the rectangle.

length	m
width	m

Answer 1

Perimeter= 2 (length + width)

let length = l, and, width =w

if the length is 3m less than twice the width, then, l = 2w-3

Perimeter= 2 (l+w)

substitute l with 2w-3

now, perimeter = 2 (2w-3 + w)

= 2 (3w-3)

= 6w-6

we know that the perimeter is 30m

therefore,perimeter : 6w-6 =30m

6w = 36m

w=6m

since l = 2w-3,

l = 2(6) -3

l = 9m

therefore, width = 6m, and length = 9m

Answer 2

P of a rectangle is 2w +2L =perimeter

then. 2w + 2 L = 30. But also Length is 3 less than twice the width.

L = 2w - 3

Use substitution to put the two equations together.

2w + 2(2w - 3) = 30. No it's a simple algebra problem.

2w + 4w - 6 = 30

6w - 6 = 30

6w = 36

w = 6. then. L = 2(6) -3 = 9

Check. 2(6) + 2( 9) = 12 + 18 = 30. Check.