Although not given in the question, but we will have to assume that temperatures of A and B are same.nA​nB​​​=pA​VA​/RTpB​VB​/RT​=pA​VA​pB​VB​​ρ=8Nm−2=(p+4S/rB​)×(4/3)π(rB​)3(p+4S/rA​)×(4/3)π(rA​)3​(S= surface tension )​Substituting the values, we getnA​nB​​=6