The Potential Difference between 2 points

[simion]

Homework Statement

What is the potential difference between points a and b in the diagram?
http://imgur.com/Ubr4A

Homework Equations

The Attempt at a Solution

I have calculated the currents to be:
I1=0.30A
I2=0.65A
I3=0.35A
What I tried doing was (0.30*5) - 0.35= 1.15 V but it's not right. Any help?

 

[azizlwl]

What is the value of V1?
http://img820.imageshack.us/img820/5158/cctb.jpg

 

[simion]

Sorry, it's 12.0 V

 

[gneill]

Homework Statement

What is the potential difference between points a and b in the diagram?
http://imgur.com/Ubr4A

Homework Equations

The Attempt at a Solution

I have calculated the currents to be:
I1=0.30A
I2=0.65A
I3=0.35A
What I tried doing was (0.30*5) - 0.35= 1.15 V but it's not right. Any help?

How did you arrive at that last expression? What does it represent?