Question

The length of a rectangle is six times its width.

If the perimeter of the rectangle is 70, find its length and width.

Answer 1

`l = 6w - - - - 1 \\ \\ 2l + 2w = 70 - - - - - 2 \\ \\ solving \: simultaneously \\ put \: l = 6w \: into \: 2 \\ 2(6w) + 2w = 70 \\ 12w + 2w = 70 \\ 14w = 70 \\ w = 5 \\ \\ l = 6w \\ l = 6(5) \\ l = 30`