Sequence And Series Question 288
Question: The first term of an A.P. is 2 and common difference is 4. The sum of its 40 terms will be
[MNR 1978; MP PET 2002]
Options:
A) 3200
B) 1600
C) 200
D) 2800
Show Answer
Answer:
Correct Answer: A
Solution:
First term $ a=2 $ and common difference $ d=4 $ and $ n=40 $ . Then $ S_{n}=\frac{n}{2}[2a+(n-1)d] $ $ =20[4+39\times 4]=20[4+156] $ $ =160\times 20=3200 $ .
BETA
