What is the sum of the first 17 terms of an arithmetic progression if the first term is -20 and last term is 28?
A. 68
B. 156
C. 142
D. 242
Answer: Option A
Solution(By Examveda Team)
First term of AP = a = -20 and last term = l = 28Number of terms = n = 17
$$\eqalign{ & {\text{Sum of AP}} = \frac{{\text{n}}}{2}\left( {{\text{a}} + {\text{l}}} \right) \cr & = \frac{{17}}{2}\left( { - 20 + 28} \right) \cr & = 17 \times 4 \cr & = 68 \cr} $$
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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