Answer:
830 Ω
Step-by-step explanation:
For the resistors connected in series the voltage flowing through them is different while the current flowing through them is the same.
The reason for the different voltages flowing through each resistor in series is due to the resistance that each resistor preceding the other poses to the voltage that is passed through it. the formula used for calculating resistance of resistors in series is = R1 + R2 + R3 while for calculating resistance in parallel is = 1/R1 + 1/R2 + 1/R3 = 1/Ret
R1 + R2 + R3 = 150 + 60 + 620 = 830 Ω