A) 8
B) 9
C) 10
D) 11
Correct Answer: C
Solution :
Since \[^{n}{{C}_{2}}\,-\,n\,=35\] Þ \[\frac{n!}{2!\,\,(n-2)!}-n=35\] Þ \[n(n-1)-2n=70\] Þ \[{{n}^{2}}-3n=70\] Þ \[{{n}^{2}}-3n-70=0\] Þ \[(n+7)\,\,(n-10)=0\] Þ \[n\,\,=\,\,10\].
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