If the first term of an A.P. is 2 and common difference is 4, then the sum of its 40 term is
A. 3200 B. 1600 C. 200 D. 2800 Answer: Option AShow Answer
Solution(By Apex Team)
$\begin{aligned}&\text{ In an A.P. }\\
&a=2\text{ and }d=4,n=40\\
&\therefore S_n=\frac{n}{2}[2a+(n-1)d]\\
&=\frac{40}{2}[2\times2+(40-1)\times4]\\
&=20[4+39\times4]\\
&=20\times(4+156)\\
&=20\times160\\
&=3200\end{aligned}$
Related Questions On Progressions
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A. 22B. 25
C. 23
D. 24
Find the first term of an AP whose 8th and 12th terms are respectively 39 and 59.
A. 5B. 6
C. 4
D. 3
Find the 15th term of the sequence 20, 15, 10 . . .
A. -45B. -55
C. -50
D. 0
The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is
A. 600B. 765
C. 640
D. 680
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