true or false question

Question

true or false At a production level of x units a small business has a cost of C(x)=2x+10 dollars and revenue of R(x)=3x dollars. Given this information the marginal profit at a production level of 10 units is "-1$/unit."

Answer 1

Cost = C(x) = 2x+10

Revenue = R() = 3x

Profit = R-C = 3x-2x-10 = x-10

Marginal Profit = (R-C)' = 1

find Marginal Profit when x=10

Marginal Profit is a constant = 1 at all output levels

so False, it doesn't = -1

Average Profit = (R-C)/x = (x-10)/x = 1- 10/x

at x=10, Average Profit = 1-10/10 = 1-1 = 0