Answer:
27
Step-by-step explanation:
Set up a proportion.
1 day / (2/3 cup) = x/ 18 cups Cross Multiply
1 day * 18 cups = 2/3 cup * x Multiply both sides by 3
1 day * 18 cups * 3 = 2x
54 day cups = 2x cups Divide by 2
54 day cups/2 cups = x
27 days (The cups cancel)
