At the school, 20 lamps of 60 W and 10 lamps of 40 W are simultaneously turned on. Determine the current

At the school, 20 lamps of 60 W and 10 lamps of 40 W are simultaneously turned on. Determine the current in the common part of the circuit for a voltage of 220V.

The total power of the lamps is P = 20 * 60 W + 10 * 40 W = 1600 W.
Lamps in a 220 volt network are connected in parallel. The current in the common section is equal to the sum of the currents through each lamp and should provide a total power of 1600 W at a voltage of 220 V.
P = Ud * Id, where P – power, Ud – effective voltage, Id – effective current.
Id = P / Ud = 1600 W / 220 V = 7.27 A.
Answer: 7.27 A.