To determine the amount of milk that David should be adding, we need to generate and expression that would relate the number of strawberries and the number of cups. From the problem statement, it is said that the number of strawberries is directly proportional to the number of cups of milk. We write it as:
X α Y where X represents the number of strawberries and Y represents the number of cups of milk
To get rid of the proportionality sign, we introduce a proportionality constant k. We calculate this by using the initial conditions given.
X = kY
at X = 14 strawberries Y = 2 1/2 cups of milk = 5/2 cups
14 = k(5/2)
k = 28/5
At X = 203
X = kY
203 = 28/5 (Y)
Y = 145/4 or 36 1/4 cups of milk needed