Kaplan 10th Edition DT Q16

Kaplan's Book

16) This problem asks us to find the current through the 4 Ohm resistor. Current through a series circuit is constant, so when I see this problem, I immediately start thinking of how to simplify this into a series circuit. Using the parallel resistance formula, we can simplify the 6 and 3 Ohm resistor into a single resistor in series with the 4 Ohm resistor.

Where R is resistance

We can simplify this further and find the equivalent resistance by summing the resistors in series.

Where R is resistance

Now we can use Ohm's Law to find the current through the circuit. Since current is constant in a series circuit, the current through the equivalent resistor R[3,6,4] will be equal to the current through the single resistor R[4].

Where V is voltage, I is current, and R is resistance

Answer: B