NO.PZ2020011303000067
问题如下：
A portfolio consists of 100 shares worth USD 20 each and 200 shares worth USD 30 each. What is the change in the value of the portfolio (in USD) as a function of the returns (i.e., the percentage change in share prices)?
解释：
△P=2000×△r1+6000×△r2，where r1and r2 are the returns on the stocks.
题目问：一个组合P有100只A股票，每只20$，200只B股票，每只30$，求股票组合的价格变化公式（function of thereturns）？
△P=2000×△rA+6000×△rB
这个和上一题有什么区别？
