A macaroni and cheese recipe calls for 4/7 cup of flour for every 2 1/5 cup of milk. To make a bigger batch, the chef uses 4 cups of flour. Which of the following would be the amount of milk needed for the bigger batch?
A. 15 1/5 cups
B. 15 2/5
C. 12 8/15 cups
D. 15 cups
To find the required number of cups of milk, we need to set up a proportion equation. If we let x be the required number of cups and cups of flour as numerator and cups of milk in denominator, then the result proportion becomes:
We cannot multiply mixed fractions with any number, so we change 2 1/5 into an improper fraction as
The proportion equation becomes
Cross-multiply to solve for x
As a mixed fraction, 77/5 becomes 15 2/5. Therefore, to make a bigger batch, the chef needs 15 2/5 cups of milk.
Therefore, the Correct Answer is B.