A classmate's home is equipped with a TV, a washing machine and two lights. The normal working current is 200mA, 1a, 300mA and 25mA respectively. If the current in the circuit is not allowed to exceed 3a, how many lights can he install at most?

A classmate's home is equipped with a TV, a washing machine and two lights. The normal working current is 200mA, 1a, 300mA and 25mA respectively. If the current in the circuit is not allowed to exceed 3a, how many lights can he install at most?

1A=1000mA,3A=3000mA
The number of lamps n = (3000-200-1000-300-25) / 300 = 1475 / 300 = 4.92
Only 4 for safety