i think you meant to say: "The amount of money that a salesperson makes varies directly as the total amountof money made fromsales" otherwise the question makes no sense, since you did not tell us how many sales were made, you just told us the value of a single sale. so i will assume the question is to be done as i described above.

Now, we say two numbers x and yvary directlyor aredirectly proportionalif there is a constant k, such that:

x = k*y

we say two numbers x and yvary indirectly, or inverslyor areinversly proportionalif there is a constant k, such that:

x = k*(1/y) = k/y

k is called theconstant of variationor theconstant of proportionality

let x be the amount of money the salesperson makes

let y be the total amount of money made on a sale, then we have

x = k*y

when x = 7500, y = 120000, so

7500 = 120000k

=> k = 7500/120000 = 1/16

so our constant of proportionality is 1/16

how much will he or she make if he or she sells a house for $150,000? well, we simply need to find x when y = 150000

now x = (1/16)y

=> x = (1/16)(150000)

=> x = 9375

so the salesperson makes $9375

since y varies inversly to x^2, we haveb) Ifyvaries inversely asx^2, andy= 2 whenx= 4, what is the constant of variation?

y = k/(x^2)

=> k = y(x^2)

when y = 2, x = 4

=> k = 2(4^2)

=> k = 32