justin charges $21 per linear foot to install a wood fence. it costs him $19 per linear foot plus $4000 to buy materials and hire installers each month. how many linear feet of fencing would he need to install each month to break even?

Question

anonymous · Answer

Let's add up the cash flows. $$P = 21 \cdot x - 19 \cdot x - 4000$$where P is justin's profit and x is the number of feet he installs. We want to solve for x when Justin breaks even, meaning a profit of zero.

anonymous · Answer

that gives me -2000 but in my book its 2000? so how did you do it?