Ptotal​=PA∘​XA​+PB∘​XB​550=PA∘​×41​+PB∘​×43​PA∘​+3PB∘​=550×4…(i) In second case Ptotal​=PA∘​×51​+PB∘​×54​PA∘​+4PB∘​=560×5…(ii) Subtract (i) from (ii)∴PB∘​=560×5−550×4=600As PA∘​=400