Answer: $22
Step-by-step explanation:
Opportunity cost may be explained as the 'cost' or 'loss' incurred by deciding to pick or choose an alternative over another.
From the context above, Cost incurred may be in two forms :
The amount paid on the chosen alternative + the cost forgone on the option ignored.
By choosing to go see a movie, $12 was paid, that is the opportunity cost for choosing to see a movie while ignoring working as a math tutor.
If he had chosen to work as a math tutor, an additional $10 would have been earned, $45 - $35 = $10
Total opportunity cost = $(12 + 10) = $22