To find the cost, \( c \), of each bag of lemons, you can divide the total cost by the number of bags. The equation can be expressed as follows:
\[ c = \frac{19.75}{5} \]
So, the completed equation that models the cost of each bag of lemons is:
\[ c = \frac{19.75}{5} \]
Calculating that gives:
\[ c = 3.95 \]
Thus, each bag of lemons costs $3.95.