To simplify the expression \( (6b + 4r) - (2b + r) \), we can start by distributing the negative sign across the second set of parentheses:
\[ (6b + 4r) - (2b + r) = 6b + 4r - 2b - r \]
Next, we can combine like terms:
- Combine the \( b \) terms: \( 6b - 2b = 4b \)
- Combine the \( r \) terms: \( 4r - r = 3r \)
Putting it all together, we have:
\[ 4b + 3r \]
So, the simplified expression for the total cost after returning 2 bags of beans and 1 bag of rice is:
\[ 4b + 3r \]