whats the best yacht brand? i want a yacht thats i can cruise around in, fish in, entertain a little in, and something that i can spend days on vacation over night and cook and stuff whats the best footage for a yacht of that purpose? and please teach me with these words that i have have seen on yachts , like what do they mean….a express yacht? a coupe yacht? a sedan yacht? a motor yacht? a cruiser yacht? what am i looking for ? which one of those do i want to be looking at? and i really seem to grow really interested in the marquis 40 SC and the 50 as well…are those good yachts? do they fit my needs?

The owner of a luxury motor yacht that sails among the 4000 Greek islands charges $620/person/day if exactly 20 people sign up for the cruise. However, if more than 20 people sign up (up to the maximum capacity of 90) for the cruise, then every fare is reduced by $6 for each additional passenger. Assume at least 20 people sign up for the cruise and let x denote the number of passengers above 20.
(a) Find a function R giving the revenue/day realized from the charter.