12. What is the purchasing power parity theorem? (LC 9.7 ) 13. Explain the concept of interest rate parity. What does this concept imply about the long-run profit opportunities from investing in international markets? What market conditions must prevail for the concept to be valid? (L.69.7) 14. What are some reasons why interest rate parity may not hold in spite of the economic forces that should ensure the equilibrium relationship? (l.9.9-7 15. One form of the interest rate parity equation appears as 1+rUSt=(1/St)(1+rUKt)Ft where both the spot and forward rates are expressed in terms of dollars for pounds or direct exchange rates. How would the equation be written if the exchange rates were indirect-that is, pounds for dollars? (LG 9.7)