Answers

2015-02-15T18:30:18+05:30

2 digit no.divisible by 3 are 12,15,18,21........99

so a=12  d=3  an=33

an= a+(n+1)d

ans is =30

follow this method then u will get the answer after that

sn=n/2(a+1)

30/2(12+99)

15*111

1665

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