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Re: Mgmat Divisibility [#permalink]
30 Nov 2008, 10:02
(k2 + 4k + 3)=(k+1)(k+3), so we are asked is (k+1)(k+2)(k+3) divisible by 4?
1) k can be 8,16,24 etc. so (k+1)(k+2)(k+3) is product of 3 consequtive integers such as 9x10x11. It is 'yes or no' question and we have the answer 'no'. Suff 2) - k is an even integer and can be 2,8,14 etc. (k+1)(k+2)(k+3) can be divisible by 4 if k=2, and can not if k=8. Insuff.