Was hoping someone could provide some clarification with this question. Stuck on most parts. Thanks

Exercise 1 (7.5 marks): Consider two identical countries in our standard overlapping generations model. In each country, the population of every generation is 100, and each young person wants money balances worth 10 goods. There are $100 of country a money and E400 of country b money. The exchange rate is fixed at 1. There are no foreign-currency controls, and the monetary authorities do not cooperate. Each country is willing to raise up to 500 goods in taxes on their old citizens to defend the exchange rate. a. What is the value in goods of a dollar? Of a euro? b. Find the value of a dollar if people abandon use of the euro. Find the value of a euro if people abandon use of the dollar. c. To be free from speculative attack, a country's commitment to defend the exchange rate must be sufficient to purchase all of its currency if it is offered for foreign exchange. Which of these two countries is most likely to be subject to a speculative attack