A 3-Ω and a 1.5-Ω resistor are wired in parallel and the combination is wired in series to a 4-Ω resistor and a 10-V emf device. The current in the 3-Ω resistor is ..

Answer 1

R_eff for the parallel resistors is 1/(1/3 + 1/1.5) or 1 ohm.

This is in series with 5 ohm resistor: R_circ = 5 ohm.

Overall current is 10V/5Ω = 2 amps

Now you can find the voltage drop across the 4 ohm resistor. (Ohm's law --> V)

The voltage left after you subtract the drop in voltage is the voltage across both the 3 ohm and 1.5 ohm resistors. You can use Ohm's Law to solve for I in the resistor.