yangsta8 wrote:

For positive integer Z, is the expression (Z + 2)(Z^2 + 4Z + 3) divisible by 4?

1. Z is divisible by 8.

2. (Z+1)/3 is an odd integer.

This is my approach...

GIVEN:

(z+1)(z+2)(z+3) are consecutive integers...

We know that the multiple of 4 appears in this pattern: 1,2,3,(4),5,6,7,(8),9,10,11,(12),...

As you have noticed, after a multiple of 4, it will be followed by 3 non-multiple of 4...

1.

If z is a multiple of 4, then z+1,z+2,z+3 are all non-multiple of 4 based on the pattern above...

SUFFICIENT.

2.

Let z+1 = 3: (3)(4)(5) is divisible by 4

Let z+1 = 9: (9)(10)(11) is not divisible by 4

INSUFFICIENT.

Answer: A

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