Who knows where this is from?

Four individuals pool money together to start a new business and agree to split the profits equally. n invests $6,000, x invests $2,000, y invests $8,000 and z invests $4,000. if the profits for the first month were $100,000, y receives than if the profits were divided in proportion to how much they invested.

If g^-1(x) is the inverse of g (x) which statement must be true

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.