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555-605 (Medium)|   Algebra|      
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ProfChaos
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If x, y and z are positive integers, can the value of (x + y 19 Nov 2020, 20:03
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C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

25% (medium)

Question Stats:

67% (00:52) correct 33% (01:08) wrong based on 46 sessions

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If x, y and z are positive integers, can the value of (x + y + z) equal 3?

(1) xy = 1

(2) xz = 1

Source - Indian MBA college entrance test
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C
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chetan2u
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GMAT Focus 1: 735 Q90 V89 DI81
Posts: 11,229
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If x, y and z are positive integers, can the value of (x + y 19 Nov 2020, 20:11
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ProfChaos
If x, y and z are positive integers, can the value of (x + y + z) equal 3?

(1) xy = 1

(2) xz = 1

Source - Indian MBA college entrance test
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Not a great question at all.

If xy=1, then CAN x+y+z=3?
Of course yes, it can be. When? When z=1.
If you had written ‘Is x+y+z=3?’, then it would not be sufficient as we do not know z.
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ProfChaos
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Joined: 11 Apr 2020
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GMAT 1: 660 Q49 V31
GMAT 1: 660 Q49 V31
Posts: 120
Kudos: 366
If x, y and z are positive integers, can the value of (x + y 19 Nov 2020, 20:20
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chetan2u
ProfChaos
If x, y and z are positive integers, can the value of (x + y + z) equal 3?

(1) xy = 1

(2) xz = 1

Source - Indian MBA college entrance test

Not a great question at all.

If xy=1, then CAN x+y+z=3?
Of course yes, it can be. When? When z=1.
If you had written ‘Is x+y+z=3?’, then it would not be sufficient as we do not know z.
Show more

I didnt like this question. I had marked E for it
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TestPrepUnlimited
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GMAT 1: 780 Q51 V45
GRE 1: Q170 V167
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If x, y and z are positive integers, can the value of (x + y 19 Nov 2020, 21:12
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ProfChaos
If x, y and z are positive integers, can the value of (x + y + z) equal 3?

(1) xy = 1

(2) xz = 1

Source - Indian MBA college entrance test
Show more

I think the question is supposed to be "Is x + y + z = 3?" We have the condition x, y, z are all positive integers, so we need x, y, z all equal to 1 to get x+y+z = 3.

Statement 1:

x = 1 and y = 1 because x and y have to be positive integers. We don't know z, insufficient.

Statement 2:

x = 1 and z = 1. We don't know y, insufficient.

Combined:

Now we know everybody is equal to 1 so combined sufficient.

Ans: C
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ProfChaos
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GMAT 1: 660 Q49 V31
GMAT 1: 660 Q49 V31
Posts: 120
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If x, y and z are positive integers, can the value of (x + y 19 Nov 2020, 22:01
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chetan2u
ProfChaos
If x, y and z are positive integers, can the value of (x + y + z) equal 3?

(1) xy = 1

(2) xz = 1

Source - Indian MBA college entrance test

Not a great question at all.

If xy=1, then CAN x+y+z=3?
Of course yes, it can be. When? When z=1.
If you had written ‘Is x+y+z=3?’, then it would not be sufficient as we do not know z.
Show more

So the use of 'Can x + y + z = 3' vs 'Is x + y + z = 3' the make or break factor for this question?

If it is 'Can..' then answer will be D
St 1 alone : xy=1 and x,y,z are positive integers (i.e. x,y,z >0) therefore x=y=1 and if z=1, x+y+z=3
St 2 alone : xz=1 and x,y,z are positive integers (i.e. x,y,z >0) therefore x=z=1 and if z=1, x+y+z=3

If it is 'Is...' then the answer will be C
St 1 alone : xy=1 and x,y,z are positive integers (i.e. x,y,z >0) therefore x=y=1 but we dont know the value for z. Insufficient
St 2 alone : xz=1 and x,y,z are positive integers (i.e. x,y,z >0) therefore x=z=1 but we dont know the value for y. Insufficient
Combining St1 and St2, we get, x=y=z=1, therefore x+y+z=3

chetan2u TestPrepUnlimited
Correct me if I am wrong
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