What are the alleged advantages of a fixed over a flexible exchange rate system? How would the

Question:

What are the alleged advantages of a fixed over a flexible system? How would the advocates of flexible exchange rates reply?
Exchange Rate
The value of one currency for the purpose of conversion to another. Exchange Rate means on any day, for purposes of determining the Dollar Equivalent of any currency other than Dollars, the rate at which such currency may be exchanged into Dollars...