The CENTRAL idea of the article is developed by . A explaining how long it can take to pay off a mortgage or student loan with different percentage rates of interest B contrasting the amount that an average percentage of sales tax costs on large and small purchases C arguing that banks should charge lower percentage interest rates on credit cards to help consumers D providing examples of common real-life situations that use percentages and how to calculate them

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.