Can someone with a few questions? for some of them i just need my answer checked.

1.the trunk of a pine tree will be cut up to make boards.
´the trunk is 52 feet long.
´the base of the trunk is a circle 1.5 feet across.
´the trunk tapers gradually to a point at the top.
which expression best models the volume of the trunk?
a. pi*.75^2*52
b. pi*1.5^2*52
c.1/3*pi*.75^2*52
d.1/3*pi*1.5^2*52

Problems and applications q5 four roommates are planning to spend the weekend in their dorm room watching old movies, and they are debating how many to watch. here is their willingness to pay for each film: willingness to pay (dollars) shen antonio dmitri jake first film 10 9 8 3 second film 8 7 6 2 third film 6 5 4 1 fourth film 4 3 2 0 fifth film 2 1 0 0 within the dorm room, the showing of a movie a public good. if it costs $12 to rent a movie, the roommates should rent movies in order to maximize the total surplus. suppose the roommates choose to rent the optimal number of movies you just indicated and then split the cost of renting equally. this means that each roommate will pay $ .