Atheater has tickets at $6 for adults, $3.50 for students, and $2.50 for children under 12 years old. a total of 278 tickets were sold for one showing with a total revenue of $1300. if the number of adult tickets sold was 10 less than twice the number of student tickets, how many of each type of ticket were sold for the showing?

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.