A) 12
B) 13
C) 14
D) 15
Correct Answer: C
Solution :
[c] \[{{1}^{st}}terms\to 1,\,\,{{2}^{nd}}\,terms=2,\,\,{{4}^{th}}\,term\to 3,\] \[{{7}^{st}}terms\to 4,{{11}^{th}}terms\to 5,......\] Series is \[1,\,\,2,\,\,4,\,\,7,\,\,11,...\] \[{{a}_{n}}=1+\frac{n(n-1)}{2}=\frac{{{n}^{2}}-n+2}{2}\] If \[n=14,\] then \[{{a}_{n}}=92,\] If \[n=15,\] then \[{{a}_{n}}=106.\]
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