Two unknown resistors A and B are connected together. When they are connected in series their combined resistance is 15 Ω. When they are connected in parallel, their combined resistance is 3.3 Ω. What are the resistances of A and B?
A)15 Ω and 5 Ω
B)5 Ω and 10 Ω
C)2.5 Ω and 5 Ω
D)32Ω and 20 Ω
E)10 Ω and 30Ω

Question

Quizplus · Accepted Answer

When resistors are in series, their resistances add up: R_A + R_B = 15 Ω. When in parallel, the formula is 1/R_parallel = 1/R_A + 1/R_B. Solving these equations gives R_A = 5 Ω and R_B = 10 Ω.

Two Unknown Resistors a and B Are Connected Together