Question

A combined circuit has two resistors in parallel (10.0 ohms and 14.0 ohms) and another in series (5.0 ohms). If the power source is 9.0 volts, what is the current?

Answer 1

Let the value of the two resistors in parallel be R ohms. Then\[\frac{1}{R}=\frac{1}{10}+\frac{1}{14}\ .....(1)\]
Now you need to solve equation (1) to find R. Then the total combined resistance in the circuit is
\[R _{total}=R+5\]
the current in the circuit is given by:
\[I=\frac{V}{R _{total}}=\frac{9}{R +5}\]