Three resistors R1=5ohms, R2=3ohms, and R3=4ohms are connected in series to each other. A voltmeter connected in parallel to resistor R2 measures voltage of 6V. What is the net voltage in the circuit?

Answer 1

the same current flows through all the resistors.
I = E2/R2 = 6/3 = 2 amps
Now E=IR across the other resistors.
Total voltage is the sum across all three R's.