Sequence And Series Question 486
Question: The solution of the equation $ (x+1)+(x+4)+(x+7)+………+(x+28)=155 $ is
Options:
A) 1
B) 2
C) 3
D) 4
Show Answer
Answer:
Correct Answer: A
Solution:
We have $ (x+1)+(x+4)+………+(x+28)=155 $ Let $ n $ be the number of terms in the A.P. on L.H.S. Then $ x+28=(x+1)+(n-1)3 $
$ \Rightarrow $ $ n=10 $
$ \therefore $ $ (x+1)+(x+4)+……+(x+28)=155 $
$ \Rightarrow $ $ \frac{10}{2}[(x+1)+(x+28)]=155 $
$ \Rightarrow $ $ x=1 $ .
BETA
