Diagram: http://gyazo.com/0b719e6d399ad894d2c48ce06d994672 1. The problem statement, all variables and given/known data In the figure the resistances are R1 = 0.77 Ω and R2 = 1.8 Ω, and the ideal batteries have emfs ε1 = 2.1 V, and ε2 = ε3 = 3.5 V. What are the (a) current (in A) in battery 1, (b) the current (in A) in battery 2 and (c) the current (in A) in battery 3? (d) What is the potential difference Va - Vb (in V)? 2. Relevant equations V=IR Kirchoff's Loop Rules 3. The attempt at a solution Okay, for some reason I solved a part of this or two before and hoped to get back to it. For part (a), I set up the equation of I being the current and R being the resistance; B being battery: I= B2-B1/(4R1+R2) And I got the answer .287A and then multiplied that by 2 and got the first part which is .587A. I understand the logic of its the potential difference divided by the equivalent resistance but why is that multiplied by 2, any reason for that? I didn't understand. For parts (b)+ (c), I tried to set it up in a similar way but they are both wrong: For part (b): B2-B1/(4R1+R2) and I got .287A For part (c): I did the same equation as above putting in B3 instead of B2 and got .287A Part (d) I was able to do by finding the potential difference between points (a) and (b) which I took the .287A value that I calculated in (b) and (c) and set it up like this: ΔV=-I2R2^2+(3.5V) which comes out to 2.98V which was correct. I could use some help with this problem, I understand how the equation to solve B is found out, but I don't understand why you would have the EQ resistance to find the first battery, rather than the resistance the battery goes through. Could use a nice explanation on that. Thanks! If someone could help with doing it the Kirchhoff rule way, I tried to assign currents with directions but for some reason I get something completely different from the correct answer I got in part (a). I have a test on this material Tuesday and I REALLY need to do well, I blanked out on the first exam and forgot everything and did really, really bad :uhh:. I really appreciate it! Thank you!