Answer Explanation
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.