Come up with a math formula for my word problem

 i want to start selling an automatic kind of floss for $18.50per unit. i will.invest 30k to start up and hope to recieve at least a 50% profit by 12 months. how much do i increase the price per month? If the rate of sales double every year for 4 years and triples on the 5th year, what is my total profit?

With my annual salary as a dental hygienist at 80k, what will be my total income after the first year of selling  this floss and working be?

Come up with a formula for my word problem and graph it.

*change numbers if needed.