Consider an economy with two types of firms, S and I. S firms all move together. I

Question:

Consider an economy with two types of firms, S and I. S firms all move together. I firms move independently. For both types of firms, there is a 60% probability that the firms will have a 15% return and a 40% probability that the firms will have a – 10% return. What is the volatility (standard deviation) of a that consists of an equal investment in 20 firms of
(a) Type S,
(b) Type I?

Portfolio
A portfolio is a grouping of financial assets such as stocks, bonds, commodities, currencies and cash equivalents, as well as their fund counterparts, including mutual, exchange-traded and closed funds. A portfolio can also consist of non-publicly...