问题如下：
Based on Exhibit 1, what is the foreign exchange gain resulting from Transaction 3 on the 31 December 2016 financial statements?
选项：
A.NVK1.70 per ton
B.NVK90.75 per ton
C.NVK248.54 per ton
解释：
A is correct.
On Ambleu’s balance sheet, the cost included in the inventory account is the translation of ₤B27,000/ton into Norvoltian krone on the purchase date. Ambleu could have paid this amount on the purchase date but chose to wait 45 days to settle the account. The inventory cost is determined using the ₤B/NVK exchange rate of 4.1779 on the purchase date of 1 June 2016. ₤B27,000/₤B4.1779/NVK = NVK6,462.58/ton
The cash outflow is the amount exchanged from the Norvoltian krone to the Bindiar franc to pay the ₤B27,000/ton owed for the inventory 45 days after the transaction date. This payment uses the ₤B/NVK exchange rate of 4.1790 on the settlement date of 15 July 2016.
₤B 27,000/₤B4.1790 per NVK = NVK6,460.88/ton
Foreign exchange gain = Inventory cost – Cash payment
= NVK6,462.58 – NVK6,460.88
= NVK1.70/ton
Thus, Ambleu’s cash outflow is less than the cost included in the inventory account, and NVK1.70/ton is the realized foreign exchange gain relating to this transaction. By deferring payment for 45 days, and because the Bindiar franc decreased in value during this period, Ambleu pays NVK1.70/ton less than the inventory cost on the purchase date of 1 June 2016. Thus, Ambleu will report a foreign exchange gain in its 2016 net income.
解析：存货是在2016年6月1日购买的，应付账款为27000₤B，当日汇率是4.1779₤B/NVK，当日的应付账款应该是以本币计价的，所以转换为本币是27,000/4.1779= 6,462.58。2016年7月15日付款，当日汇率是4.1790₤B/NVK，实际支付27,000/4.1790= 6,460.88，比账上所计的A/P少，相当于公司赚了，foreign exchange gain =6,462.58- 6,460.88=1.7
请问这题为什么不用报表日的汇率？当问题怎么问时才需要用报表日汇率进行对比呢？
