The figure shows a section of three long charged cylinders centered on the same axis. Central cylinder A has a uniform charge qA= +3q0. What are the charges of qb and qc if E is 0 on point > a) 1 ( between A & B ) b) 2 ( between B & C ) c) 3 ( out side the cylinders ) My solutions were based on the concept of vectors a) qB= +3q0, qC= -6q0 b) qB= +3q0, qC= +6q0 c) That's impossible. ( the other choices were impossible ) But they were wrong. Could you explain what's wrong with my solutions ?