bigtreezl wrote:

if n is an integer greater than 6, which of the following must be divisible by 3?

(A) n (n+1) (n-4)

(B) n (n+2) (n-1)

(C) n (n+3) (n-5)

(D) n (n+4) (n-2)

(E) n (n+5) (n-6)

PLEASE SOLVE WITHOUT PLUGGING NUMBERS

(A) n (n+1) (n-4) = n (n+1) (n-4+6) = n (n+1) (n+2)

This is equivalant to a multiplication of any 3 contineous integers > 6. In this case, the product (of any 3 contineous integers > 6)must be a multiple of 3.

(B) n (n+2) (n-1) = n (n+2) (n-1+3) = n (n+2) (n+2)

This is not equivalant to a multiplication of any 3 contineous integers > 6. In this case, the product may/may not be a multiple of 3.

(C) n (n+3) (n-5) = n (n+3) (n-5+6) = n (n+3) (n+1)

This is not equivalant to a multiplication of any 3 contineous integers > 6. In this case, the product may/may not be a multiple of 3.

(D) n (n+4) (n-2) = n (n+4) (n-2+3)= n (n+4) (n+1)

This is not equivalant to a multiplication of any 3 contineous integers > 6. In this case, the product may/may not be a multiple of 3.

(E) n (n+5) (n-6) = n (n+5) (n-6+9) = n (n+5) (n+3).

This is not equivalant to a multiplication of any 3 contineous integers > 6. In this case, the product may/may not be a multiple of 3.

Then its A.

_________________

Verbal: http://gmatclub.com/forum/new-to-the-verbal-forum-please-read-this-first-77546.html

Math: http://gmatclub.com/forum/new-to-the-math-forum-please-read-this-first-77764.html

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT