Hi, testpost:

It is better to open a new thread for a new problem.

Anyway, here's my answer:

Question 1:

Provided (n*v) liter of gas at A, How far theoretically

a vessle can go? [Consider n>1, measure it using s]

n*s. Oops, now the boat is stuck there.Question 2:

Provided (n*v) liter of gas at A, How for theoretically

a vessle can go if all vessel are required to go back

to A?

n*s/2, waste all the gasoline for nothingQuestion 3:

Gas sales at c cents per liter at A. at B, s km away from

A, what is the cheapest price (theoretically) for gas?

[Only from gas cost perspective]

n*c/(n-1)Question 4:

Add this requirement to Q3: All vessel must goback to A

at end of the day?

n*c/(n-2)5. How many liter of gas must be shipped out to B per

day to maintain 10c cents per liter at B?

You mean 10 times higher? then 20v/96. Where you can find the cheapest gas in US continent?

This is a guess: Texas??