Subject: General Aptitude · Chapter: Number System · Exam: · Marks: · Difficulty:
If $\left(12^{n}+1\right)$ is divisible by 13, then $n$ is
(a)1 only
(b)12 only
(c)any odd integer
(d)any even integer
Answer
Answer (as printed): C
Explanation
$\left(x^{n}+a^{n}\right)$ is divisible by $(x+a)$ when $n$ is odd. $$\therefore\left(12^{n}+1\right) \text { is divisible by }(12+1) \text { i.e. } 13 \text { when } n \text { is odd. }$$
Explanation as extracted from the printed page; notation may be imperfect.