It is currently 19 Nov 2017, 00:16

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Is a product of three integers XYZ a prime? (1) X=Y (2) Z=1

Author Message
SVP
Joined: 03 Feb 2003
Posts: 1603

Kudos [?]: 308 [0], given: 0

Is a product of three integers XYZ a prime? (1) X=Y (2) Z=1 [#permalink]

### Show Tags

19 Jun 2003, 08:18
00:00

Difficulty:

(N/A)

Question Stats:

100% (01:06) correct 0% (00:00) wrong based on 17 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Is a product of three integers XYZ a prime?

(1) X=–Y
(2) Z=1

Kudos [?]: 308 [0], given: 0

Manager
Joined: 03 Jun 2003
Posts: 83

Kudos [?]: 1 [0], given: 0

Location: Uruguay

### Show Tags

19 Jun 2003, 12:29
C?

From 1, maybe or maybe not
From 2, nothing

Together, you now it is impossible to get a prime

Kudos [?]: 1 [0], given: 0

Manager
Joined: 12 Mar 2003
Posts: 59

Kudos [?]: 1 [0], given: 0

### Show Tags

19 Jun 2003, 15:33
Ans : C

1) Z could be -ve thus => insuff
2) X*Y could be prime => insuff

Combined :

X*Y*Z = -ve number

and since X=-Y, X*X can never be prime

Ans NO => Suff

Kudos [?]: 1 [0], given: 0

SVP
Joined: 03 Feb 2003
Posts: 1603

Kudos [?]: 308 [0], given: 0

### Show Tags

19 Jun 2003, 22:37
tzolkin wrote:
Ans : C

1) Z could be -ve thus => insuff
2) X*Y could be prime => insuff

Combined :

X*Y*Z = -ve number

and since X=-Y, X*X can never be prime

Ans NO => Suff

You move in the right direction, either set is not sufficient. Combine -- the product is –X^2, a negative number can NEVER be a prime! If X=0, then tha product is 0, which is not prime either. Thus, C.

Kudos [?]: 308 [0], given: 0

Current Student
Joined: 28 Dec 2004
Posts: 3345

Kudos [?]: 322 [0], given: 2

Location: New York City
Schools: Wharton'11 HBS'12

### Show Tags

06 Feb 2007, 12:03
I would say this has to be B...

x*y*z=prime?

1) x=-y, lets see if x=2, then y=-2 x*y=-4*if z=-1 then product not a prime..suppose x=-1 y=1 then -1*z if z=-3 then product is 3 (prime) Insuff

2) z=1, taking above example.....

1*-2*2=-4 not a prime..you can try other numbers...it will always never be a prime..B has to be it...

I wish styolar was around..to verify.but i think B is the right

Kudos [?]: 322 [0], given: 2

VP
Joined: 22 Oct 2006
Posts: 1436

Kudos [?]: 196 [0], given: 12

Schools: Chicago Booth '11

### Show Tags

06 Feb 2007, 12:29
fresinha12 wrote:
I would say this has to be B...

x*y*z=prime?

1) x=-y, lets see if x=2, then y=-2 x*y=-4*if z=-1 then product not a prime..suppose x=-1 y=1 then -1*z if z=-3 then product is 3 (prime) Insuff

2) z=1, taking above example.....

1*-2*2=-4 not a prime..you can try other numbers...it will always never be a prime..B has to be it...

I wish styolar was around..to verify.but i think B is the right

B is insuff

because 1 * 1 * 1 Not Prime
2 * 1 * 1 Prime

Kudos [?]: 196 [0], given: 12

06 Feb 2007, 12:29
Display posts from previous: Sort by