For the given perimeter find the length and width of the rectangle with the greatest area use whole numbers only

So, the formula for the perimeter of a rectangle is 2l+2w=p. We know that p=80. Our options for w and l are: 30 and 10, 20 and 20, 25 and 15. To find the are we multiply the length by the width. 30*10=300, 20*20=400, 25*15=375. The greatest area is with the length and width both being 20.