The total effective resistance of several resistors in SERIES is just the sum of all the individual resistances.
So the effective resistance of ten 120-ohm resistors in series is
(120 + 120 + 120 + 120 + 120 + 120 + 120 + 120 + 120 + 120) .
A much easier way to write it is . . . (10) x (120) .
Total effective resistance = 1,200 ohms .
