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mehrasa
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1) we have 5 people and want to form a 3 member groups.. in how many ways we can form a group of 3 in a way that Ann is in all groups...
To me, the answer is 12... we have 3 places ---, for the first place we put Ann, second place, 4 people out of 5 (except for Ann) and third place 3 people can be seated...also, the order is not important.. then: 4*3*1= 12
2) we have 5 members of a council, G,A,M,R,T.. in how many ways committee can be seated in a way that R and T sit always next to each other?
for solving this problem, we need to consider R and T as one member so we have {G,A,M, {R-T}}
then the total ways is 4! and the # of orders, R and t can position is 2!--> the answer is 4!*2!(this is the part i can not understand, why we multiply this two while we know that when we have indistinguishable objects (R and T) we need to say 5!(total)/ 2!
could you please clarify me.. thnx
To me, the answer is 12... we have 3 places ---, for the first place we put Ann, second place, 4 people out of 5 (except for Ann) and third place 3 people can be seated...also, the order is not important.. then: 4*3*1= 12
2) we have 5 members of a council, G,A,M,R,T.. in how many ways committee can be seated in a way that R and T sit always next to each other?
for solving this problem, we need to consider R and T as one member so we have {G,A,M, {R-T}}
then the total ways is 4! and the # of orders, R and t can position is 2!--> the answer is 4!*2!(this is the part i can not understand, why we multiply this two while we know that when we have indistinguishable objects (R and T) we need to say 5!(total)/ 2!
could you please clarify me.. thnx
