In a survey 27% of the people chose salads over a meat dish and in all 81 people chose salads. how many people were in the survey

The john deere company has found that revenue,in dollars, from sales of heavy-duty tractors is a function of the unit price p, in dollars, that it charges. if therevenue r is r(p)= -1/2p^2 +1900pa)how much revenue will the company generate if they sell 700 tractors? b) how many tractors does the company want to sell to maximize the revenue?