NO.PZ2022061307000045
问题如下：
Question
A price-weighted index series is composed of the following three stocks:
If stock Z completes a three-for-one split at the end of Day 1, the value of the index after the split (at the end of Day 2) is closest to:
选项：
A.31.7.
B.32.3.
C.29.9.
解释：
SolutionA is correct. The value of the price-weighted index is determined by dividing the sum of the security values by the divisor, which is typically set at inception to equal the initial number of securities in the index. In the case of a stock split, the index provider must adjust the value of the divisor by dividing the sum of the constituent prices after the split by the value of the index before the split. This adjustment results in a new divisor that keeps the index value at the same level as before the split. The new divisor will then be used to calculate the index value after the split.
Index before the split =
= 30
New divisor, X: 30 =
X = 1.67
Index after the split =
= 31.7
B is incorrect. It calculates the changes in prices and uses it to derive the new index.
C is incorrect. It uses price after split to calculate the new divisor.
拆股前：（10+20+60）/3=30 拆股后：（12+19+22+22+22）/5=19.4 是哪里错了呀？
