A classroom has a length that is 6 meters shorter than its width. If the perimeter is 30m, what is the length and width?

Question

Please put working out within the question rather than just the question please. Thank you!

Answer 1

The parent function for the perimeter of a rectangle is:

P=2W+2L

"The length is 6 meters shorter than the width" implies that L=W-6

So substitute into the perimeter equation: P=2W+2(W-6)

Simplify (optional) P=4W-12

P=30, so 30=4W-12

Solve for W, you will get 10.5

Looking at line 3: L=W-6, so L=10.5-6

L=4.5

W=10.5

Answer 2

w=L+6

2(L+w)=30

divide 2nd equation by 2

L+w=15

substitute 1st equation into 3rd

L+L+6=15

2L=15-9

divide by 2

L=9/2 = 4.5 meters long

w=L+6 = 4.5+6 = 10.5 meters wide