I thought the solution would come from adding $150 and $25, but it turns out I am wrong. Can someone help walk me through this? I', not sure how to calculate the total oppurtunity cost.

Ming lives in Seattle and recently bought a $150 ticket to attend a Seattle Seahawks game. He is a huge fan, so even though the ticket is pricey it is well below his willingness to pay of $200. However, as game day approaches, Ming receives an invitation from his friend, Cassandra, to spend the day at the Museum of Pop Culture touring a big exhibit on Marvel superheroes. The museum visit would only cost $25, but Ming (being a big Marvel fan too) would be willing to pay $125. What is his opportunity cost of going to the Seattle Seahawks game? Ming's total opportunity cost of going to the Seattle Seahawks game is $ 175. (Enter a numeric response using an integer.)