Answer
Total Resistance = 72 ohms
Step-by-step explanation
In order to find total resistance of the resistors connected in series we will add them all.
Total Resistance = ∑Rn where n is the number of all resistors.
Four resistors in series are of 12, 20, 16, 24 ohms
Total Resistance = R1 + R2 + R3 + R4
Total Resistance = (12 + 16 +20 +24) ohm
Total Resistance = 72 ohms
The current through each resistor in series is equal, but the voltage is not.