A company makes pens. They sell each pen for $10.
Their revenue is represented by R = 10 x.
The cost to make the pens is $3 each with a one time start up cost of $5000.
Their cost is represented by C = 3 x + 5000.
a) Find the profit, P, (P = R - C) when the company sells 1000 pens.

b) Find the number of pens they need to sell to break even (when R = C).