Please show all work and please do not get the answer from another previously answered question, thank you in advance

The ER is real/$ .10, or $10 buys 1 real. The change in the ER is what percentage wise, if at the end of the year the ER is r/$ .011111111, or $ 90 buy real 1? Show it in two ways. The one is real per dollars and the other is dollars per real.

B. The Nigerian naira versus the US dollar is 7 to 1, i.e., 7 naira buy one dollar. The ER between the Swiss franc and the US dollar is one Swiss franc to 1.1 US $. Finally, the naira trades 7.02 per one Swiss franc. What kind of triangular arbitrage will induce the highest profit for you? Assume you start with $1 million, or the equivalent of it in the other currencies. (Note we are asking for the highest profit and not any profit.)