What is the maximum amount of silver in grams that can be plated out of 4.8L of an AgNO3 solution containing 3.3% Ag by mass?

I assume that is 3.3% w/w Ag (not AgNO3) in the 4.8 L of solution. You don't tell me the density of the solution so I will assume the density of the solution is 1 g/mL so 4.8 L has a mass of 4,800 grams.

3.3% w/w means 3.3 g Ag/100 g solution. The g Ag in 4,800 g solution is
3.3 x (4,800 g/100 g) = ? g Ag in the 4.8 L. That's the most you can plate out if you plate all of it.