Sequence And Series Question 227
Question: The sum of the series $ \frac{1}{2}+\frac{1}{3}+\frac{1}{6}+…….. $ to 9 terms is
[MNR 1985]
Options:
A) $ -\frac{5}{6} $
B) $ -\frac{1}{2} $
C) 1
D) $ -\frac{3}{2} $
Show Answer
Answer:
Correct Answer: D
Solution:
Given series $ \frac{1}{2}+\frac{1}{3}+\frac{1}{6}+…….. $ Here $ a=\frac{1}{2} $ , common difference $ d=-\frac{1}{6} $ and $ n=9 $ .
$ \Rightarrow $ $ S_9=\frac{9}{2}[ 2\times \frac{1}{2}+(9-1)( -\frac{1}{6} ) ]=-\frac{3}{2} $ .
BETA
