please answer for B, C, and D

Nigerian naira Floated. On Friday June 17,2016 , the Central Bank of Nigeria (CBN) abandoned the Nigerian naira's (NGN) fixed exchange rate and allowed the currency to float. Previously fixed against the U.S. dollar at NGN 198.85=1.00 USD, the naira closed at NGN 278.77/USD on Monday June 20, the first day of trading following the float. The naira quickly floated (sunk) to NGN 325.47/USD by August 18. Similarly, the naira fell from NGN 223.7769=1.00 EUR to NGN 318.0579/EUR on June 20, and NGN 344.1463/EUR on August 18. a. What was the percentage change in the value of the Nigerian naira versus the dollar the first trading day? b. What was the percentage change in the value of the naira versus the dollar by August 18, 2016? c. What was the percentage change in the value of the Nigerian naira verus the euro the first trading day? d. What was the percentage change in the value of the naira versus the euro by August 18, 2016? a. What was the percentage change in the value of the Nigerian naira versus the dollar the first trading day? The percentage change in the value of the Nigerian naira versus the dollar the first trading day was (Round to two decimal places.) b. What was the percentage change in the value of the naira versus the dollar by August 18,2016? You answered: 40.19 The percentage change in the value of the naira versus the dollar by August 18,2016 was %. (F Correct answer: 28.67 (Answer tolerance \pm 0.02 )