Sequence And Series Question 65
Question: If $ a,\ b,\ c,\ d,\ e,\ f $ are in A.P., then the value of $ e-c $ will be
[Pb. CET 1989, 91]
Options:
A) $ 2(c-a) $
B) $ 2(f-d) $
C) $ 2(d-c) $
D) $ d-c $
Show Answer
Answer:
Correct Answer: C
Solution:
$ a,\ b,\ c,\ d,\ e,\ f $ are in A.P. So $ b-a=c-b=d-c=e-d=f-e=K $ Where $ K $ is a common difference. Now, $ d-c=e-d $
$ \Rightarrow $ $ e+c=2d $ . $ e\text{–}c+2c=2d\Rightarrow e-c=2(d-c) $ . Trick: Check by putting $ a=1,\ b=2,\ c=3,\ d=4,\ e=5 $ and $ f=6 $ .
BETA
