I think the perimeter is 64. If you divided the 4 sides of the window by 256, you get 64. Sorry if it's not right. I hope it is. c;
Hi the picture has the answer and work, if you have any questions feel free to ask!!
Side Side Side is the answer
The unit rate for the 1st one is: $0.19 / ounce
The unit rate for the 2nd one is: $0.16 / ounce
The 36 ounce box would be the better buy because it is less per ounce than the 24 ounce box