The period for the following function y=2cos(2/3)x -6 is... HELP PLEASE ITS NOT HARD I JUST DONT GET IT!!!

Ben is three times as old as samantha, who is two years older than half of michel's age. if michel is 12. how old is ben?

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.

1. if events a and b are non-overlapping events, how do you find the probability that one or the other occurs? 2. what does it mean if p(a or b) equals 1?