Suppose two cities are considering tearing down their stadiums to build new ones. In one city, the old stadium cost $5 million to build, while in the other city, the old stadium cost $50 million to build. If all else is equal, what can we say about how the costs of the old stadiums should affect the cities' decisions?

These are the options for the question:

A. They should be more willing to tear down the $5 million stadium, because it cost less to build.

B. They should be more willing to tear down the $50 million stadium, because it cost more to build.

C. The cost to build the old stadium shouldn't be considered.

And this is the correct answer:

A. They should be more willing to tear down the $5 million stadium, because it cost less to build.

Explanation:

City A will likely be more willing to tear down its old stadium because it costed $5 million to build. City B, on the other hand, will have to think twice because a stadium that costed $50 billion to build could have more value than it seems, or the City could simply not have enough money to build a better new stadium (something that would probably cost more than $50 billion to do).

The Cost to build the old stadium shouldn't be considered - The cities shouldn't consider the cost to build the old stadium, which is a sunk cost. They should be examining whether the benefits of tearing down the old stadium and putting up a new stadium outweigh the costs of that decision.