To solve this, you can set up an equation. Make the length of the shortest side x, so the 2 sides double the length will equal 2x. Since they all equal the perimeter of 36, do x + 2x + 2x =36. These values all represent the sides(2 longer, one short). Combine like terms to get 5x=36 then divide by 5 to find the value of x. x=7.2in meaning the shorter side is 7.2 inches while the longer sides are both 14.4 inches each since they are double in size.
Let p = the normal price.
Then 7(p - .75)= 2.80
Divide by 7: p - .75 = .40 and p = 1.15
8/0.72 = 0.09
Per ounce cost $0.09
This gonna help you