Suppose that a firm can borrow dollars at 8% or Burundi francs at 14%. If the Burundi franc is expected to move from USD / BIF 58 at the beginning of the year to USD / BIF 61 at the end of the year, then the expected dollar cost of the Burundi franc loan is? The answer is 8.39%, but can you show me the steps/ formula used to get there?

Thanks