I'm stuck on one hw problem that is part of the extra credit portion. I know that I should be able to do it, but I am just missing something.

Here's the problem:

So I figure that there are three equations that I can write:Two resistances, R1 and R2, are connected in series across a 12-V battery. The current increases by 0.18 A when R2 is removed, leaving R1 connected across the battery. However, the current increases by just 0.11 A when R1 is removed, leaving R2 connected across the battery. Find (a)R1 and (b)R2.

(i) V/(R1+R2) = I

(ii) V/R1 = I + 0.18A

(iii) V/R2 = I + 0.11A

I've tried to algebraically solve for the individual resistors and I just can't seem to do it. I think I am approaching the problem correctly but perhaps I am doing something wrong partway through.

Thanks for your help.