Analyst, Peter Smith, evaluates a fixed income portfolio. There are two bonds in the portfolio, bond A and bond B. He projects that probability of bond A downgrading on its rating is 60% within a year. The probability of bond B upgrading is 20%. Assume that a bond rating will either upgrade or downgrade within a year. The rating changes of both bonds are independent. Required:
Compute the probability of both bond A and bond B upgrading on their ratings.

An office supply company conducted a survey before marketing a new paper shredder designed for home use. in the survey, 80 % of the people who tried the shredder were satisfied with it. because of this high satisfaction rate, the company decided to market the new shredder. assume that 80 % of all people are satisfied with this shredder. during a certain month, 100 customers bought this shredder. find the probability that of these 100 customers, the number who are satisfied is 69 or fewer.