To keep the ratio equivalent, you need to divide

To solve the division of the fractions \( \frac{2}{1} \div \frac{1}{7} \):

First, remember that dividing by a fraction is the same as multiplying by its reciprocal. So, we have:

\[ \frac{2}{1} \div \frac{1}{7} = \frac{2}{1} \times \frac{7}{1} \]

Now, perform the multiplication:

\[ \frac{2 \times 7}{1 \times 1} = \frac{14}{1} = 14 \]

Therefore, the result of \( \frac{2}{1} \div \frac{1}{7} \) is 14.

This means Elyse’s recipe needs 14 cups of lemonade concentrate for each cup of water.