DC circuitsQuestion 326 of 1506

Two groups of resistors are in series. Group 1 is two 30 Ω resistors in parallel. Group 2 is two 20 Ω resistors in parallel. What is the total resistance?

  1. 10 Ω
  2. 50 Ω
  3. 100 Ω
  4. 25 Ω
Show answer

Correct answer: 25 Ω

Group 1 is 15 Ω and group 2 is 10 Ω. In series they add to 25 Ω.

Source: Troubleshooting Motors and Controls (Dickson-Self), 2.1: Combination Series and Parallel Circuits

Practice dc circuits

Questions last reviewed: 18 October 2026