Combination of Resistors: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Combination of Resistors. Understanding the underlying formula is key to arriving at the correct answer below:

Resistance $R \propto \frac{1}{A}$. Given $\frac{A_1}{A_2} = \frac{3}{1}$ and the thicker wire's resistance $R_1 = 10 \Omega$. The thinner wire has resistance $R_2 = 3R_1 = 30 \Omega$. Total series resistance $R_s = R_1 + R_2 = 10 + 30 = 40 \Omega$.