there are n students in a class a group of 3 goes to appughar with teacher and the same set ofchildrendoesn't go more than once .it is found that the teacher goes to appughar84times more than a particular child find n?????ans n=10

Dear Akhilesh

no. of times teacher goes to appughar = nC3

no. of times a particular child goes to appughar = (n-1)C2      bcoz we have to select 2 students out of n-1 students

According to question

nc3-(n-1)C2=84

after solving

(n-1)(n-2)(n-3)=504

n=10

All the best

AKASH GOYAL
AskiitiansExpert-IITD

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