问题如下：
A dealer provides the following quotes:
Another dealer is quoting the ZAR/SEK cross-rate at 1.1210. The arbitrage profit that can be earned is closest to:
选项：
A.ZAR 3671 per million SEK traded.
B.SEK 4200 per million ZAR traded.
C.ZAR 4200 per million SEK traded.
解释：
C is correct.
The ZAR/SEK cross-rate from the original dealer is (1.0218/0.9149) = 1.1168, which is lower than the quote from the second dealer. To earn an arbitrage profit, a currency trader would buy SEK (sell ZAR) from the original dealer and sell SEK (buy ZAR) to the second dealer. On 1 million SEK the profit would be
SEK 1,000,000 × (1.1210 – 1.1168) = ZAR 4200
考点： cross-rate
解析：原交易对商ZAR/SEK交叉率为(1.0218/0.9149)= 1.1168，低于第二个交易商的报价。为了赚取套利利润，投资者应当从原始交易商那里购买SEK (sell ZAR)，然后将SEK 卖给第二交易商(buy ZAR)。100万SEK的利润是
SEK 1,000,000 × (1.1210 – 1.1168) = ZAR 4200
老师，好：
我研究了半天还是没懂单位为啥是按c选项的写法。答案的那个计算方法我也没看明白。看前面解释说是协会规定，那意思就是碰见类似的题目算完，直接把两边单位换一下选答案么？我按何老师上课说的把汇率写法变成斜杠统一形式，算出来的就是b选项。能否写下具体的计算过程。谢谢。
