These Running Shoes Just Became the Most Expensive Trainers in the World On July 23, a pair of one of the rarest and most coveted running shoes became the most expen- sive trainers ever sold. The final sale price? A whopping $437,500. What made these shoes so valuable was their history: There were only 12 first editions of the Nike Moon shoes and they were handed out to runners at the 1972 Olympic Trials. Source: runnersworld.com, July 24, 2019

a. If the price of an ordinary pair of running shoes is $50, what can we infer about the marginal utility of an ordinary pair of run- ning shoes and the marginal utility of a pair of Nike Moon running shoes for a person who buys one pair of ordinary running shoes and one pair of Nike Moon running shoes?

b. Why might the marginal utility from a pair of Nike Moon running shoes decrease more rapidly than the marginal utility from ordinary running shoes?