GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 19 Oct 2019, 11:04

### 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

# If x and y both are integers, what is the value of x+y?

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 25 Sep 2018
Posts: 427
Location: United States (CA)
Concentration: Finance, Strategy
GMAT 1: 640 Q47 V30
GPA: 3.97
WE: Investment Banking (Investment Banking)
If x and y both are integers, what is the value of x+y?  [#permalink]

### Show Tags

03 Nov 2018, 10:03
2
00:00

Difficulty:

55% (hard)

Question Stats:

61% (01:39) correct 39% (01:31) wrong based on 85 sessions

### HideShow timer Statistics

If x and y both are integers, what is the value of x+y?

1) $$x(x^2y)$$ =1
2)$$y(y^2x)$$=1

_________________
Why do we fall?...So we can learn to pick ourselves up again
Director
Joined: 31 Jul 2017
Posts: 512
Location: Malaysia
GMAT 1: 700 Q50 V33
GPA: 3.95
WE: Consulting (Energy and Utilities)
Re: If x and y both are integers, what is the value of x+y?  [#permalink]

### Show Tags

03 Nov 2018, 10:18
1
Abhi077 wrote:
If x and y both are integers, what is the value of x+y?

1) $$x(x^2y)$$ =1
2)$$y(y^2x)$$=1

Consider -

x = 1,y = 1,
x = -1,y = -1

Hence, E.
_________________
If my Post helps you in Gaining Knowledge, Help me with KUDOS.. !!
Director
Joined: 27 May 2012
Posts: 902
Re: If x and y both are integers, what is the value of x+y?  [#permalink]

### Show Tags

26 Nov 2018, 12:19
1
Abhi077 wrote:
If x and y both are integers, what is the value of x+y?

1) $$x(x^2y)$$ =1
2)$$y(y^2x)$$=1

Dear Moderator,
Found this DS question, in the PS section of number properties , hope you will do the needful. Thank you.
_________________
- Stne
Math Expert
Joined: 02 Sep 2009
Posts: 58445
Re: If x and y both are integers, what is the value of x+y?  [#permalink]

### Show Tags

26 Nov 2018, 12:23
stne wrote:
Abhi077 wrote:
If x and y both are integers, what is the value of x+y?

1) $$x(x^2y)$$ =1
2)$$y(y^2x)$$=1

Dear Moderator,
Found this DS question, in the PS section of number properties , hope you will do the needful. Thank you.

____________________________
Moved to DS. Thank you.
_________________
GMAT Club Legend
Joined: 18 Aug 2017
Posts: 5020
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: If x and y both are integers, what is the value of x+y?  [#permalink]

### Show Tags

26 Nov 2018, 17:10
Abhi077 wrote:
If x and y both are integers, what is the value of x+y?

1) $$x(x^2y)$$ =1
2)$$y(y^2x)$$=1

From 1 : value of x & y can be +/-1
From 2: Same as 1 , two values of x & y +/- 1

IMO E
Senior Manager
Joined: 13 Jan 2018
Posts: 342
Location: India
Concentration: Operations, General Management
GMAT 1: 580 Q47 V23
GMAT 2: 640 Q49 V27
GPA: 4
WE: Consulting (Consulting)
Re: If x and y both are integers, what is the value of x+y?  [#permalink]

### Show Tags

26 Nov 2018, 20:51
As the product of two integers is 1, we only two choices. Either -1 or 1.

Now consider x and y as -1.
Statement 1) True
Statement 2) True

x+y = -2

Now consider x and y as 1.
Statement 1) True
Statement 2) True

x+y = 2

Even after combining the statements we can't get a unique answer for x+y. So answer is E
_________________
____________________________
Regards,

Chaitanya

+1 Kudos

if you like my explanation!!!
Intern
Joined: 07 Oct 2018
Posts: 1
Re: If x and y both are integers, what is the value of x+y?  [#permalink]

### Show Tags

27 Nov 2018, 04:06
Abhi077 wrote:
If x and y both are integers, what is the value of x+y?

1) $$x(x^2y)$$ =1
2)$$y(y^2x)$$=1

From eqn1, we know x= y^-3
and from eqn2, y= x^-3

Combining, we get x=(( x^-3)^-3) or 1= x^5. This implies that x is positive. Hence, x+y should take the positive values of x and y respectively. (C)
Math Expert
Joined: 02 Aug 2009
Posts: 7984
Re: If x and y both are integers, what is the value of x+y?  [#permalink]

### Show Tags

27 Nov 2018, 04:53
1
nishidesai wrote:
Abhi077 wrote:
If x and y both are integers, what is the value of x+y?

1) $$x(x^2y)$$ =1
2)$$y(y^2x)$$=1

From eqn1, we know x= y^-3
and from eqn2, y= x^-3

Combining, we get x=(( x^-3)^-3) or 1= x^5. This implies that x is positive. Hence, x+y should take the positive values of x and y respectively. (C)

You are wrong in the highlighted portion...$$(x^{-3})^{-3} = x^{-3*-3}=x^9.........x^8=1$$, so x can be 1 or -1
just substitute x and y as -1, this will also satisfy the equation.
$$x^{-3}x^{-3}=x^{-6}$$
_________________
Re: If x and y both are integers, what is the value of x+y?   [#permalink] 27 Nov 2018, 04:53
Display posts from previous: Sort by