Find the current through resistor R using superposition.

E1=20V; E2=10V; R=10ohm; R1=2ohm; R2=5ohm

here's my try:
I'=1.25A
I''=0.25A

I get stuck when I try to find the current that comes from the current generator (Ig)
and R3 is not given

Does Ig participate on the current through R.

if not then I=I'-I''=1A

Thanks in advance

 

You can find the current in this circuit with help of current divider rule
http://en.wikipedia.org/wiki/Current_divider

 

R3 value is not given
The current source is in series with R3
I can't apply the current divider rule if I don't know R3

(The current source and resistance are in series.Is that allowed ?...)

 

You don't need to know R3 to find current flowing through 10R resistor.
R3 is in series with constant current source so R3 will have no effect on the current.
Only the constant current source determines the value of a current flowing in this branch.