Quantitative Aptitude Ques 856
Question: If $ n $ is even, then $ (6^{n}-1) $ is divisible by
Options:
A) 37
B) 30
C) 35
D) 6
Show Answer
Answer:
Correct Answer: C
Solution:
- If $ x $ is even, then let $ n=2x, $ tor some x.
Now, $ 6^{n}-1=(6^{2x}-1)=36^{x}-1 $
$ =(36-1)({36^{x-1}}+{36^{x-2}}+…+1) $
$ =(35)({36^{x-1}}+{36^{x-2}}+…+1) $
Hence, the number is divisible by 35.