Last visit was: 14 Dec 2024, 22:38 It is currently 14 Dec 2024, 22:38
Close
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
Your Progress

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
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,114
Own Kudos:
17,810
 []
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,114
Kudos: 17,810
 []
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
Omkar.kamat
Joined: 04 Mar 2016
Last visit: 20 Feb 2017
Posts: 22
Own Kudos:
Given Kudos: 2
Location: India
Posts: 22
Kudos: 15
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
vitaliyGMAT
Joined: 13 Oct 2016
Last visit: 26 Jul 2017
Posts: 299
Own Kudos:
Given Kudos: 40
GPA: 3.98
Posts: 299
Kudos: 808
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
Omkar.kamat
Joined: 04 Mar 2016
Last visit: 20 Feb 2017
Posts: 22
Own Kudos:
Given Kudos: 2
Location: India
Posts: 22
Kudos: 15
Kudos
Add Kudos
Bookmarks
Bookmark this Post
vitaliyGMAT
MathRevolution
If x and y are positive integers, \(x^y^-^2\)=?

1) \(x^2\)=1
2) \(y^2\)=4

1) \(x^2\)=1

Gives us x = +/- 1, but we are told that x,y >0 and we have only one option x=1 and \(1^{any - power} = 1\). Sufficient.

2) \(y^2\)=4

Gives us y = +/- 2. Bu again according to the question y>0, hence y=2. We have \(x^{2-2} = x^0 = 1\). Sufficient.
But xy-2 is asked... U get X or Y values in individual conditions. How do u get y value in cond 1 or x value in Cond 2 ??

Omkar Kamat
When The Going Gets Tough, The Tough Gets Going !!
User avatar
AkshdeepS
Joined: 13 Apr 2013
Last visit: 14 Dec 2024
Posts: 1,451
Own Kudos:
Given Kudos: 1,001
Status:It's near - I can see.
Location: India
Concentration: International Business, Operations
GPA: 3.01
WE:Engineering (Real Estate)
Products:
Posts: 1,451
Kudos: 1,722
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Omkar.kamat
vitaliyGMAT
MathRevolution
If x and y are positive integers, \(x^y^-^2\)=?

1) \(x^2\)=1
2) \(y^2\)=4

1) \(x^2\)=1

Gives us x = +/- 1, but we are told that x,y >0 and we have only one option x=1 and \(1^{any - power} = 1\). Sufficient.

2) \(y^2\)=4

Gives us y = +/- 2. Bu again according to the question y>0, hence y=2. We have \(x^{2-2} = x^0 = 1\). Sufficient.
But xy-2 is asked... U get X or Y values in individual conditions. How do u get y value in cond 1 or x value in Cond 2 ??

Omkar Kamat

When The Going Gets Tough, The Tough Gets Going !!


When x = 1 it does not matter what the power is as the rule for exponents says any number raised to "0" will yield "1" as result. So st 1 is sufficient.

For st 2, when y = 2 the exponent becomes 0, so it does not matter what x is, the expression will yield "1" as result. So st 2 is sufficient.

So D is the correct answer because both statements individually gives you "1" as value of \(x\)\(^{y-2}\)

Hope this helps.
User avatar
ashikaverma13
Joined: 19 Aug 2016
Last visit: 24 Jan 2019
Posts: 127
Own Kudos:
Given Kudos: 59
Location: India
GMAT 1: 640 Q47 V31
GPA: 3.82
Products:
GMAT 1: 640 Q47 V31
Posts: 127
Kudos: 318
Kudos
Add Kudos
Bookmarks
Bookmark this Post
In the first condition, y could also be 1 which satisfies y>1. in that case it will be 1 raised to the power of -1.



When x = 1 it does not matter what the power is as the rule for exponents says any number raised to "0" will yield "1" as result. So st 1 is sufficient.

For st 2, when y = 2 the exponent becomes 0, so it does not matter what x is, the expression will yield "1" as result. So st 2 is sufficient.

So D is the correct answer because both statements individually gives you "1" as value of \(x\)\(^{y-2}\)

Hope this helps.[/quote]
User avatar
AkshdeepS
Joined: 13 Apr 2013
Last visit: 14 Dec 2024
Posts: 1,451
Own Kudos:
Given Kudos: 1,001
Status:It's near - I can see.
Location: India
Concentration: International Business, Operations
GPA: 3.01
WE:Engineering (Real Estate)
Products:
Posts: 1,451
Kudos: 1,722
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ashikaverma13
In the first condition, y could also be 1 which satisfies y>1. in that case it will be 1 raised to the power of -1.



When x = 1 it does not matter what the power is as the rule for exponents says any number raised to "0" will yield "1" as result. So st 1 is sufficient.

For st 2, when y = 2 the exponent becomes 0, so it does not matter what x is, the expression will yield "1" as result. So st 2 is sufficient.

So D is the correct answer because both statements individually gives you "1" as value of \(x\)\(^{y-2}\)

Hope this helps.


Had it been the case of y = 1, then also it would have remained the same.

"1" raised to any exponent remains as it is. For example if \(x = 2\) then, \(2^{-1}\) becomes \(\frac{1}{2}\)

Therefore if \(x =1\) and \(y = 1\) then, \(1^{-1}\) becomes \(\frac{1}{1}\) \(= 1\)

Hope it's clear.
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,114
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,114
Kudos: 17,810
Kudos
Add Kudos
Bookmarks
Bookmark this Post
==> In the original condition, there are 2 variables (x), and in order to match the number of variables to the number of equations, there must be 2 equations, and therefore C is most likely to be the answer. By solving con 1) & con 2), you get x=-1, 1 and y=-2, 2. Since x and y are positive integers, only x=1 and y=2 are possible, and con 1) becomes \(1^y^-^2=x^2^-^2=x^0=1\).

Therefore, the answer is D.
User avatar
LeoN88
User avatar
BSchool Moderator
Joined: 08 Dec 2013
Last visit: 08 Dec 2024
Posts: 685
Own Kudos:
Given Kudos: 227
Location: India
Concentration: Nonprofit, Sustainability
Schools: ISB '23
GMAT 1: 630 Q47 V30
WE:Operations (Non-Profit and Government)
Products:
Schools: ISB '23
GMAT 1: 630 Q47 V30
Posts: 685
Kudos: 533
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Very Good Sum

x,y > 0 and Int.

#1. It says x can be 1 or -1, but we know x is +ve Int.

So, x has to be 1, answer-> 1 Sufficient

#2. y has to 2 (we know y is +ve Int.)
So, x^ (2-2) = x^0 = 1 Sufficient

E


MathRevolution
If x and y are positive integers, \(x^y^-^2\)=?

1) \(x^2\)=1
2) \(y^2\)=4
Moderator:
Math Expert
97877 posts