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If The Sum Of 1st N Integers Is 55 Then What Is N? |
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Answer» sum=n(n+1)/2 sum=55 n^2+n=55*2 n^2+n110=0 (N10)(n+11)=0 n=10,11,neglect NEGATIVE ans answer =10 sum=n(n+1)/2 sum=55 n^2+n=55*2 n^2+n110=0 (n10)(n+11)=0 n=10,11,neglect negative ans answer =10 |
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