In which set of ordered pairs is y a function of x? a. {(1.25, 6), (3, 6), (5.75, 6), (11, 6)} b. {(2, 15), (3, 12), (4, 10), (4, 8)} c. {(6, 1), (3, 8), (3, 9), (6, 12)} d. {(6.5, 10), (6.5, 0), (6.5, 9), (6.5, 12)}

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.