A Cu²⁺(aq) cell and an Ag⁺(aq) cell are connected in series to a constant 2.50 A current for 30.0 min. Calculate the mass of copper and the mass of silver deposited at their respective cathodes. (Molar masses: Cu = 63.55 g mol⁻¹, Ag = 107.87 g mol⁻¹)