7a/9bc divided by 21a/12b

If i have one apple and give you the apple, how many apples do i have?

Sasha drank 8 bottles of water everyday for a week. how many bottles of water did she drink in total?

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.