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Plz evaluate my solution - number properties

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by Night reader » Wed Dec 01, 2010 1:23 am
Are x, y, and z consecutive integers?

(1) The remainder when x + y + z is divided by 3 is 2.
(2) The remainder when xyz is divided by 3 is 1.

x,y,z ~ 3x+3

(1) (3x+3)/3=q+2/3 <> 3x+3=3q+2 <> 3x=3q-1 <> any q value should eliminate the possibility of multiple of 3. Sufficient, answer - negative
(2) xyz/3=q+1/3 <> all multiples of 3 (for consecutive integers) should have a remainder of 3, otherwise x,y,z must not be integers; Sufficient, answer - negative
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Source: — Data Sufficiency |

by shovan85 » Wed Dec 01, 2010 1:50 am
Yes. The Answer should be D.

(1) As you have shown x+y+z is always multiple of 3. So if there is a remainder 2 then x, y , z cannot be consecutive.

Sufficient.

(2) If x,y, and z are consecutive then one out of them is definitely multiple of 3. Thus, if xyz has a remainder 1 then x, y , z cannot be consecutive.

Sufficient.
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