Final answer:
If the price per box is $20, Michael will demand 1 unit of 'Bubbly' mineral water.
Step-by-step explanation:
The given table shows Michael's monthly demand for 'Bubbly' mineral water boxes at different prices.
If the price per box is $20, we need to find out how many units Michael will demand at that price.
From the given table, we can see that at the price of $20, the corresponding MWTP (Marginal Willingness To Pay) is also $20.
Therefore, Michael's demand for the 'Bubbly' mineral water boxes would be 1 unit at the price of $20.
In summary, if the price per box is $20, Michael will demand 1 unit of 'Bubbly' mineral water.