The answer to Utility maximization
A consumer buys five new college textbooks during his first year at school at a cost of $80 each. Used books cost only $50 each. When the bookstore announces that there will be a 10% increase in the price of new books and a 5% increase in the price of used books, the consumer's father offers him $40 extra. Is this consumer worse or better off after the price change? Explain.