Please Answer I am in desperate need of help.

Louis wants to carpet the rectangular floor of his basement. the basement has an area of 864 square feet. the width of the basement is 2/3 it's length. what is the length of louis's basement

Someone me! if you’re smart you can solve this!

If 30 lb of rice and 30 lb of potatoes cost ? $27.60? , and 20 lb of rice and 12 lb of potatoes cost ? $15.04? , how much will 10 lb of rice and 50 lb of potatoes? cost?