Just wondering, what level of physics is this?
I think you can use Ohm's Law.
I=V((1/R1)+(1/R2)) where I is current, V is voltage, and R is resistance.
I haven't done much on electricity so I'm not too sure.
Ohm is the SI unit for Resistance and not Current which is A for amperes
The formula in Ohm's law I = V/R is applied to each resistor in a parallel circuit to get the current following at that section.
The total current in a parallel circuit is the total current from each section of the parallel circuit.
a)What is the current through the 40.0-Ω resistor?
b)What is the total current in the circuit?
Current at 20Ω resistor - 120V/20Ω= 6A
Total current in the circuit - 6A+3A= 9A