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**1. Homework Statement**

In the circuit of Figure P28.28, determine the current in each resistor and the potential difference across the 200-ohm resistor.

**2. Homework Equations**

Kirchoff's Rules

V=IR

**3. The Attempt at a Solution**

The way I did it was like this:

I set up a system of equations-

I1 + I2 + I3 + I4 = 0

- 40 V = I2 (80Ω) - I1 (200Ω)

40 V - 360 V = I3 (20Ω) - I2 (80Ω)

- 360 V - 80 V = I4 (70Ω) - I3 (20Ω)

And I get

I1=1.83 (for 200Ω)

I2=4.07 (for 80Ω)

I3=.30 (for 20Ω)

I4=-6.2 (for 70Ω)

Then I do V=IR to get the potential difference, which I got was 366 volts.

But in the back of the book, it says the answers are:

1.00 A up in 200Ω

4.00 A up in 70 Ω

3.00 A up in 80 Ω

8.00 A down in 20 Ω

200 V

What did I do wrong