ABC26GN0291 · Number System

Subject: General Aptitude · Chapter: Number System · Exam: 2007 · Marks: · Difficulty:

The number $6 n^{2}+6 n$ for natural number $n$ is always divisible by

(a)6 only

(b)6 and 12

(c)12 only

(d)18 only

Answer

Answer (as printed): B

Explanation

6n2 + 6n = 6n (n + 1) (n = 1 ⇒ 6n2 + 6n = 12), (n = 2 ⇒ 6n2 + 6n = 36), (n = 3 ⇒ 6n2 + 6n = 72), each one of which is divisible by 6 and 12 both.

Explanation as extracted from the printed page; notation may be imperfect.