Jane Higgins, CFA, a industry analyst, doe
题型：单项选择题
问题：
Jane Higgins, CFA, a industry analyst, does research about inventory valuation. The company uses a periodic inventory system and no inventory on 31 May, 2012. The company purchases inventory as follows:
| Purchase Date | Cost per Unit | Number of Units |
| 1 May | $14.00 | 1000 |
| 3 May | $10.00 | 400 |
| 6 May | $8.00 | 1500 |
| 23 May | $10.00 | 300 |
During May, 2000 units are sold. Under the weighted average cost method of inventory valuation, cost of goods sold is closest to:（）
A.
20160
B.20625
C.31000
，m=0
，m=
，m=0
，m=
A，副线圈接有一电流表，与负载电阻串联，电流表的读数为0.1 A，在t=3T/8时，原线圈中电流的瞬时值为0.03 A。由此可知变压器的原副线圈的匝数比为 
