[{"hint": "Opportunity cost is what you give up.", "answer": "The concert experience is the opportunity cost.", "question": "You have $50. You can buy a video game or go to a concert. If you choose the game, what is the opportunity cost?"}, {"hint": "How does rain affect demand for umbrellas?", "answer": "Demand increases while supply stays the same, so the price tends to rise.", "question": "Explain what happens to the price of umbrellas when it starts raining heavily."}]