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
Solution(By Examveda Team)
The third term t3 = a + 2dThe ninth term t9 = a + 8d
t3 + t9 = 2a + 10d = 8
Sum of first 11 terms of an AP is given by
$$\eqalign{ & \Rightarrow {S_{11}} = \frac{{11}}{2}\left[ {2a + 10d} \right] \cr & \Rightarrow {S_{11}} = \frac{{11}}{2} \times 8 \cr & \Rightarrow {S_{11}} = 44 \cr} $$
Related Questions on Progressions
Find the first term of an AP whose 8th and 12th terms are respectively 39 and 59.
A. 5
B. 6
C. 4
D. 3
E. 7
The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is
A. 600
B. 765
C. 640
D. 680
E. 690
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