how would you answer questions 8,9&10

8. The problem of the double coincidence of wants can be avoided if a. trade is organized in a central market. b. money is used to facilitate exchanges. c. barter trades are encouraged. d. both (a) and (b) of the above. 9. Suppose that velocity and output are constant, and that the quantity theory and Fisher effect are both correct. If nominal interest rates are 6 percent and inflation is 2.5 percent, it follows that the a. money supply growth rate is 2.5 percent. b. real interest rate is 8.5 percent. c. real interest rate is 2.5 percent. d. money supply growth rate is 6 percent. 10. High and unexpected inflation has a greater cost a. for savers who invest in government bonds than borrowers with a fixed-rate mortgage. b. for those who hold a little money than for those who hold a lot of money. c. for those whose wages increase by as much as inflation, than those who are paid a fixed nominal wage. d. for the elderly on Social Security Benefits than for individual on fixed nominal pensions. (Bonus questions)