Даю 19 баллов за решение n=3
R34=R3+R4=300+400=700 R234=R2*R34/(R2+R34)=200*700/(200+700)≈255.6 Ro=R1+R234=100+155.6=255.6 Io=E/Ro=240/255.6≈0.94 A U34=Io*R234=0.94*155.6=146.3 B I4=U34/R4=146.3/400≈0.37 A P4=I4²*R4=0.37²*400≈53.5 Вт ==================================