To find out how many avocados Desiree needs for 1 cup of lime juice, we can start with the given ratio in the recipe: 1/4 cup of lime juice for every 4 avocados.
First, let's determine how many 1/4 cups are in 1 cup:
\[ 1 \text{ cup} = 4 \times \frac{1}{4} \text{ cup} \]
This means that 1 cup is equivalent to 4 quarters of a cup (1/4 cup).
Since 4 avocados are needed for each 1/4 cup of lime juice, for every quarter cup, Desiree can use the following formula to find the total number of avocados needed for 1 cup:
\[ \text{Number of avocados} = 4 \text{ avocados} \times \text{number of 1/4 cups in 1 cup} \]
Substituting the number of quarter cups:
\[ \text{Number of avocados} = 4 \text{ avocados} \times 4 = 16 \text{ avocados} \]
Therefore, Desiree needs 16 avocados for 1 cup of lime juice.