$9.$ Purchasing$-$power parity holds between the nations$$of Ectenia and Wiknam, where the only commodity is$$Spam$.$a$.$ In $2015,$ a can of Spam costs $4$ dollars in Ectenia$$and $24$ pesos in Wiknam. What is the exchange$$rate between Ectenian dollars and Wiknamian$$pesos$?$b$.$ Over the next $20$ years, inflation is expected to be$3\mathrm{.}5$ percent per year in Ectenia and $7$ percent per$$year in Wiknam. If this inflation comes to pass,$$what will the price of Spam and the exchange$$rate be in $2035?($Hint: Recall the rule of $70$ from$$Chapter $27.)$c$.$ Which of these two nations will likely have a$$higher nominal interest rate? Why?$$d$.$ A friend of yours suggests a get$-$rich$-$quick$$scheme: Borrow from the nation with the lower$$nominal interest rate, invest in the nation with the$$higher nominal interest rate, and profit from the$$interest$-$rate differential. Do you see any potential$$problems with this idea? Explain.