Hi there!
18 × [tex]\frac{3}{4}[/tex] = amount of ice cream in container
13.5 = amount of ice cream in container
Let's replace the number of cups by "C" :
13.5 = C × [tex]\frac{1}{3}[/tex]
Isoltate "C" by dividing each side of the equation by [tex]\frac{1}{3}[/tex]
40.5 = C
Which means that your answer is : There are 40.5 1/3-cup servings of ice creamin the container!
There you go! I really hope this helped, if there's anything just let me know! :)