financial management accounting chapter 20 question 6psa with 3 parts regarding precision systems manufacture CD burners sell 18500 units am i on the right track if not what process to calculate answer correctly what formula should used

a. need to be $104 or $4 increase cost (increase labor $23)

b. how many units to sell if leaving 100 sell price =19,240 sells (increase variable total cost 63 + 21.08 fixed 84.08 x 18500/100)

c. formula for additional 700k machinery depreciate 20% prepare schedule of estimate operating income before and after the expansion how do i go about that correctly