The perimeter of a rectangle is 400 meters. the length is 15 meters less than the width. find the length and width

Ok... Perimeter is = 2l + 2w

w being width and l being length.

We know that perimeter is equal to 400 so

400 = 2l + 2w

The length is 15 meters less than the width, so in notations, l = w - 15

We can substitute than in the equation to get 2(w-15) + 2w = 400

Expanding will give 2w - 30 + 2w = 400

Solving w gives w= 430/4 = 107.5 meters

Substituting in original equation for w to find l, 400 = 2l + 2(107.5)

400 = 2l + 215

2l = 185

l = 92.5 cm

Or you can just use the question to know that the length is 15 times less than the width, so 107.5 - 15 = 92.5

Length = 92.5 cm

Width = 107.5 cm