Tony and Patty produce skis and snowboards. The tables show their production possibilities. Each week, Tony produces  5 snowboards and 40 skis; Patty produces 10 snowboards and 5 skis. Tony's Production Possibilities Snowboards Skis (units per week) (units per week) 15 10 285040 and 0 and 10 and 20 and 30 and 40 and 50 Patty's Production Possibilities Skis (units per week) Snowboards (units per week) 829 20 and 10 and 0 and 0 5 10

a. Who has a comparative advantage in produc- ing (i) snowboards and (ii) skis?

b. If Tony and Patty specialize and trade 1 snow- board for 1 ski, what are the gains from trade?