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The sum of third and ninth term of an A.P is 8. Find the sum of the first 11 terms of the progression.

A. 44 B. 22 C. 19 D. 46 Answer: Option A
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Solution(By Apex Team)

The third term $t_{3}=a+2 d$ The ninth term $t_{9}=a+8 d$ $t_{3}+t_{9}=2 a+10 d=8$ Sum of first 11 terms of an AP is given by $\begin{aligned}&\Rightarrow S_{11}=\frac{11}{2}[2a+10d]\\ &\Rightarrow S_{11}=\frac{11}{2}\times8\\ &\Rightarrow S_{11}=44\end{aligned}$

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