Question

If ${}^{\prime }{n}^{\prime }$ is a positive integer, then $n^3+2n$ is divisible by

• A. 3
• B. 2
• C. 6
• D. 15

Answer 1

Answer: (A)

Let $P(n)=n^3+2n$
$\Rightarrow P(1)=1+2=3$
$\Rightarrow P(2)=8+4=12$
$\Rightarrow P(3)=27+6=33$
Here, we see that all these numbers are divisible by $3.$