7. Your dormitory roommate plays loud music most of the time;

you, however, would prefer more peace and quiet. You suggest that she buy some earphones. She responds that although she would be happy to use earphones, she has many other things that she would prefer to spend her money on right now. You discuss this situation with a friend who is an economics major. The following exchange takes place:

He: How much would it cost to buy earphones?

You: $15.

He: How much do you value having some peace and quiet for the rest of the semester?

You: $30.

He: It is efficient for you to buy the earphones and give them to your roommate. You gain more than you lose; the benefit exceeds the cost. You should do that.

You: It just isn’t fair that I have to pay for the earphones when I’m not the one making the noise.