A) 16
B) 18
C) 20
D) 22
Correct Answer: A
Solution :
\[{{T}_{r}}=\frac{{{(1+2+........+r)}^{2}}}{{{r}^{2}}}\,=\frac{1}{{{r}^{2}}}\,{{\left( \frac{r(r+1)}{2} \right)}^{2}}\] \[=\frac{{{r}^{2}}+2r+1}{4}\] \[\therefore \,\,\,\,\,\,\,{{T}_{7}}=16\]You need to login to perform this action.
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