Distinct four-letter sequences are formed by picking 4 letter tiles from a bag containing 11 different alphabet tiles. note that the order in which the letters are picked matters.
the probability of getting a particular four-letter sequence
need the answer asap

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?