Andrei wants to fill a glass tank with marbles, and then fill the remaining space with water. W(n) models the amount of water Andrei uses (in liters) if he uses n marbles. W(n)=32−0.05n What is the volume of each marble?

k(n) = 32 - 0.05n

Note that

k(n) + 0.05n = 32

So

Volume of Water + Volume of marbles = Total Volume

So...this implies that the volume of each marble must be 0.05 L