A student has a monthly budget of $120 to spend on either burritos, which cost $6 each, or sodas, which cost $4 each.
7. What is the opportunity cost of a burrito?
8. What is the opportunity cost of a soda?
9. The local farmer's market offers 1 bag of cilantro for $6 or 2 bags for $10. What's the marginal cost of the second bag?