which expression is equivalent to 7 3/4 - 1/2 A) -7 3/4 + (1/2) B) 7 3/4+ (-1/2) C) 1/2+ (-7 3/4) D) 1/2 + 7 3/4 please answer with a, b,c, or d

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.