If Nicola used 25% of the milk collected, that meqans she has 75% as leftover.
We are told that the leftover is 8.4 quarts of milk, that is, 8.4 equals 75%.
Therefore, we would have the following;
[tex]\begin{gathered} \frac{8.4}{x}=\frac{75}{100} \\ \text{Cross multiply and you'll have} \\ \frac{8.4\times100}{75}=x \\ \frac{840}{75}=x \\ x=11.2 \end{gathered}[/tex]That means Nicola collected 11.2 quarts of milk
