At a study session before a midterm exam you heard four of your friends chatting:
a. "I think Joshua paid too much for his backpack."
b. "I gave Eddie S20. He really needed it more than I do."
c. "I didn't go to the concert last night because tickets were $30."
d. "I did. It was the best $30 I spent this semester." Explain each statement, using utility analysis.