Riley wishes to put a string of coloured lights up around her rectangular patio. Find the total length of the string she will need if the length of her pation is 4 meters less than twice its width and the area of the patio is 30 square metres.
Don't forget your Algebra I now that you're taking calculus
w(2w-4) = 30
Solve for w, or just note that 5*6 = 30