Number of white phones =2 Number of black phones =2 Number of red phones =1 customer1 will have 3choices customer2 will have 3choices customer3 will have3choices Hence total choices =3×3×3=27 The cases not possible =BBB,RRR,WWW,RRB,RBR,BRR,RRW,RWR,WRR Possible cases =18 Probability =