A) \[9\]
B) \[18\]
C) \[27\]
D) \[36\]
Correct Answer: C
Solution :
[c] We have \[369=\frac{9}{2}[2+(9-1)d]\] \[\Rightarrow \,\,\,\,\,82=2+8d\] \[\Rightarrow \,\,\,\,\,d=10\] Now, \[a{{r}^{8}}=a+8d=1+8\times 10=81\] or \[{{r}^{8}}=81\] or \[r=\sqrt{3}\] \[\therefore \,\,\,{{7}^{th}}\] term of G.P. \[=a{{r}^{(7-1)}}=1\times {{(\sqrt{3})}^{6}}=27\]You need to login to perform this action.
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