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 58 % probability that the firm will have a 29 % return and a 42 % probability that the firm will have a negative 2 % return. What is the volatility (standard deviation) of a portfolio that consists of an equal investment in:

a. 39 firms of type S?

b. 39 firms of type I?