Example on combined Series and Parallel Circuit

Example:What is voltage on A, B, and D?
What is current on A, B, C, and D?
What is resistance on C?
What is total current and resistance?
First of all, we have to look at the diagram very carefully (The order of the questions also help us from where we have to start), we know that the voltage on D is equal to C, which is 80 V. We also know A and B have the same voltage. Using the voltage law, we can find out the voltage on A and B, which is 230 - 80 = 150 V each.
Now we get all the voltages on each component. Using ohm's law, we can find out the current on A, B, C, and D. IA= 150/30 = 5 A; IB = 150/30 = 5 A; ID = 80/40 = 2 A; IC = 10-2 = 8 A. The sum of the current on A and B is equal to that of C and D (eq. 3). A+B = C+D.
The resistance of A+B is 15 ohm The resistance on C is R = 80 [V] /8 [IC] = 10 ohm. Therefore, the resistance of C+D is 8 ohm.
We can find out total resistance of this circuit.
R = 15+8 = 23 ohm; I = 230 [V] /23 [R] = 10 A