Question 61666
The cost of producing 500 calculators is given by the cost formula 
c(x)=16000+120x Substitute x = 500 into this formula.

Cost = 16000 + 120 * 500
= $76 000


The revenue gained from selling the 500 calculators is given by 
R(x)=700x-x^2/50. Substitute x = 500 into this formula.

Revenue = 700*500 - 500^2/50
=$345 000


The profit formula is P(x)=R(x)-C(x)
Profit = $345 000 - $76 000
=$269 000


(Note that if only a few calculators were produced then the cost function would be larger than the revenue function and the profit would be negative. This would mean that a loss had been made.)