1. The problem statement, all variables and given/known data How to calculate the value of total resistance RT in the shown circuit? 2. Relevant equations 3. The attempt at a solution I used Kirchhoff` first law: i1+i2=I where i1, i2 and I are the current passing through R1, R2 and the total current in the circuit, respectively. similarly, i4+i5=I, i1+i3=i4 i3+i5=i2 Then I used Kirchhoff` second law, 20 i1+10 i4=V0 10 i2+20 i5=V0.