Write a proportion that could be used to solve for each variable.
Then solve.
18 ounces in 6 bottles
x ounces in 24 bottles
a. 18/6 = x/24; x = 72 c. 6/18 = x/24; x = 8
b. 18/6 = x24; x = 82 d. 18/6 = 24/x; x = 9