Two resistances of 5.0 22 and 7.0 2 are connected in series and the combination is connected in parallel with a resistance of 36.0 2. The equivalent resistance of the combination of three resistors is

The equivalent resistance of the circuit is calculated in two distinct steps based on the principles of series and parallel combinations:

• Step 1: Series Combination - When resistors are connected in series, their resistances are additive. The sum of the first two resistors is:
  Rseries = 5.0 Ω + 7.0 Ω = 12.0 Ω.
• Step 2: Parallel Combination - This 12.0 Ω combination is then connected in parallel with a 36.0 Ω resistor. The formula for equivalent resistance (Req) in parallel is:
  1/Req = 1/R1 + 1/R2
  1/Req = 1/12.0 + 1/36.0
• Final Calculation: Using a common denominator of 36.0:
  1/Req = (3 + 1) / 36.0 = 4 / 36.0
  Req = 36.0 / 4 = 9.0 Ω.

Thus, the equivalent resistance of the entire combination is 9.0 Ω, which aligns with Option C.