A) use ohm's law I =V/R,= 48/(3*470) = 0.034 amps = 34 milliamps
B) 16 volts across each resistor since V = IR = 0.034 amps x 470 ohms
C) minimum power = (0.034)(16) = 0.544 watts, this is 16 volts x 0.034 amperes
In a series circuit the total resistance = R1 + R2 + R3 = 1,410 ohms
The current is 48 Volts/1,410 ohms which is 34 milliamps