R2=R3,所以R2与R3并联的等效电阻为R2/2;
干路电流为2A,流过R1的为1A,则流过R2与R3并联的等效电阻的也为1A;
故R2与R3并联的等效电阻等于R1,即R2/2=R1;
故R2=R3=2R1=24Ω