(2/3a - 5) - (1/3a + 3) simplify

let m = monomial

let t = trinomial

so, m times t = t.

monomial times a trinomial = another trinomial.

i think you would have to divide the money he had saved, which is $2,000 by the time he plans on exercising which is 40 hours, and the answer you get should tell you the answer to your question.