Litres of milk at a local grocery store are priced at one for $2 or two for $3. What is the marginal cost of buying a second litre of milk?

Question

Quizplus · Accepted Answer

Buying one litre of milk costs $2.
Buying two litres of milk costs $3.
Therefore, the marginal cost of buying the second litre of milk is $1 ($3 - $2).
So, it is better to buy two litres of milk instead of buying two separate litres of milk because it saves $1.

Litres of Milk at a Local Grocery Store Are Priced