Question

If $'n '$ is a positive integer, then $n^3 + 2n$ is divisible by

• A. 3
• B. 2
• C. 6
• D. 15

Answer 1

Answer: (A)

3

Answer 2

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