Current through parallel cells with unequal EMFs

[zoya76]

1 Two cells are connected in parallel by joining the terminals together so that they both face in the same direction. One of the cells has emf 6.0 V and internal resistance 3.0 Ω, and the other cell has emf 4.0 V and internal resistance 2.0 Ω. An 8.0 Ω resistor is connected between the terminals.

a Calculate the current passing through each cell. Note: It is ok to get a negative current for your answer, it just means it is traveling in the opposite direction. (6 marks)
b Calculate the current passing through the 8 Ω resistor. (2 marks)
c Calculate the pd across the 8 Ω resistor. (2 marks)

I've tried applying the equation emf = I(R+r) to the circuit as a whole. I'm assuming that the total emf is an average of the two cells, i.e. 5V, and that the total internal resistance r is just = 3*2/3+2. Once subbed into the equation and rearranging for I, I get a total circuit current of 0.81A which I divide in a ratio of 3:2. This gives me wrong anwers though (0.484A and 0.324A) as opposed to 0.609A and 0.087A.

Thanks all x

 

[cnh1995]

Two cells are connected in parallel by joining the terminals together so that they both face in the same direction. One of the cells has emf 6.0 V and internal resistance 3.0 Ω, and the other cell has emf 4.0 V and internal resistance 2.0 Ω. An 8.0 Ω resistor is connected between the terminals.

What does that mean? Please show the circuit diagram.

I'm assuming that the total emf is an average of the two cells, i.e. 5V

That's incorrect.
Have you studied KCL and KVL?
Edit: You can look up Millman's theorem, but I don't think it would give you full credit for this problem.

 

[Dr Dr news]

If you draw a circuit diagram and sum the voltage drops around the closed loop, you should see your error.