This is just a general question... when trying to solve for the current in each resistor in a parallel circuit, how do you go about setting it up? (I know that the equation V=IR comes in handy...)
Its used to find current when resistances are hooked up in parallel with each other. Here is a wiki picture that should clear things up for you:
http://upload.wikimedia.org/wikipedia/en/4/47/Cdr.GIF [Broken]
It changes a little when we have more than two resistances. Let's consider a circuit with three parallel branches. We know that the voltage drop across any resistor in a parallel circuit is equal to that of the source:
[tex] I_x = \frac{V_s}{R_x}[/tex]
[tex]V_s = I_TR_T[/tex] <--the source voltage is equal to the total current times the total resistance.
Now substituting [itex]I_TR_T[/itex] for Vs in the first equation (Ix).
[tex]I_x = \frac{I_TR_T}{R_x}[/tex]
We can therefore conclude that the current through any parallel resistor is in fact:
[tex]I_x = \frac{R_T}{R_x}\cdot I_T[/tex]