To find out how many bags of cheese (represented by \(c\)) Edwin can buy, we need to consider the total amount he can spend, which is $20, and subtract the amount he spent on sauce, which is $8. This leaves him with $12 to spend on cheese.
Since each bag of cheese costs $3, we can set up an inequality to represent the situation:
\[3c \leq 12\]
Now, solve for \(c\):
\[c \leq \frac{12}{3}\]
\[c \leq 4\]
Edwin can buy at most 4 bags of cheese with the remaining money.