Pls do the 4th question

Dear Student
Let no.of bulbs be X where I=12A     
 Voltage = 220 V     
 Power  =  100 W * X

As,     
         P=VI
          100 W * X = 12A * 220 V
            X = (12 * 220 V) / 100 W
            THEREFORE           
            X = 43 Bulbs
Regards