The answer would be B. About 92 cubic feet. Have a good rest of your day.
F(x) = -2.5x + 135...where x is the number of weeks, and f(x) = total weight
If they have the same charge
x+x+x+x+x+x+x=-42
7x=-42
x=-6
so to check our answer
-6-6-6-6-6-6-6=-42
-12-12-12-6=-42
-24-18=-42
-42=-42
D should be the correct answer :)
