Prove each of the following. Be sure to indicate whether you are using a Direct Proof, a Contrapositive Proof, a Proof by Cases, or a Proof by Contradiction. If you use a Proof by Cases, be sure to indicate what each case is, and in each case, which type of proof you are using. (a) Prove that for an integer n, n 2 is even if and only if n is even. (b) Let a and b be integers and define c

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.