In the circuit shown, current flowing through 25 V cell is:

Given :E1=10VE2=5VE3=20VE4=30Vr1=5Ωr2=10Ωr3=5Ωr4=11ΩEquivalent resistance:1req=1r1+1r2+1r3+1r4⇒1req=15+110+15+111⇒req=1.69ΩEquivalent voltage,Eeq=[E1r1+(−E2)r2+E3r3+(−E4)r4]req⇒Eeq=[105+(−5)10+205+(−30)11]1.69⇒Eeq=4.68VUsing Kirchhof's law for second loop,−2;5+4.68+i(1.69)=0⟹i=12A