If x, y∈{0, 1, 2, 3, 4, 5} Then, which of the following are the function in the given set/
(a) f1 = {(x, y) : y = x - 1}
(b) f2 = {(x, y) : x + y < 3}
(c) f3 = {(x, y) : x > y}
(d) f4 = {(x, y) : x + y = 4}

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.

Dots sells a total of 279 t-shirts ($2) and shorts ($4). in april total sales were $670. how many t-shirts and shorts did dots sell?

Walking at a constant rate of 8 kilometers per hour, juan can cross a bridge in 6 minutes. what is the length of the bridge in meters?