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

 It is currently 23 May 2019, 08:22

### 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 belong to the set {2, 4}, and x^ky = x^(ly2−8), is kl > 2?

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 55266
If x and y belong to the set {2, 4}, and x^ky = x^(ly2−8), is kl > 2?  [#permalink]

### Show Tags

01 Oct 2018, 04:40
00:00

Difficulty:

95% (hard)

Question Stats:

42% (02:54) correct 58% (03:00) wrong based on 66 sessions

### HideShow timer Statistics

If x and y belong to the set {2, 4}, and $$x^{ky} = x^{(ly2−8)}$$, is $$kl > 2$$?

(1) $$k = −6$$

(2) $$3l − k = 3$$

_________________
Manager
Joined: 21 Jul 2018
Posts: 194
Re: If x and y belong to the set {2, 4}, and x^ky = x^(ly2−8), is kl > 2?  [#permalink]

### Show Tags

01 Oct 2018, 04:48
Submitted option C as an answer but feel like B is the answer, if anyone is able to solve with B then could you please post the solution.
_________________
______________________________
Press +1 Kudos if my post helped you a little and help me to ulcock the tests Wish you all success

I'd appreciate learning about the grammatical errors in my posts

Please let me know if I'm wrong somewhere and help me to learn
Manager
Joined: 21 Jul 2018
Posts: 194
Re: If x and y belong to the set {2, 4}, and x^ky = x^(ly2−8), is kl > 2?  [#permalink]

### Show Tags

11 Oct 2018, 11:58
Bunuel could you please provide assist to understand why D is answer.
_________________
______________________________
Press +1 Kudos if my post helped you a little and help me to ulcock the tests Wish you all success

I'd appreciate learning about the grammatical errors in my posts

Please let me know if I'm wrong somewhere and help me to learn
Intern
Joined: 05 Oct 2018
Posts: 43
Location: United States
GMAT 1: 770 Q49 V47
GPA: 3.95
WE: General Management (Other)
Re: If x and y belong to the set {2, 4}, and x^ky = x^(ly2−8), is kl > 2?  [#permalink]

### Show Tags

22 Oct 2018, 16:29
I can see how statement 1 is sufficient, but I am getting not sufficient for statement 2. Can you show how statement two is sufficient? Perhaps I made an algebraic error.

I began by equating the exponents, so we know that k*y = l*y*2 - 8 (is that the correct reading or is that supposed to be y^2?)

Statement one states that k = - 6
Plugging in, we get -6y = 2ly-8
y(2l+6) = 8
y can be either 2 or 4, which means that l can be -1 or -2
In both cases when multiplied by k = -6, we have a result > 2
Sufficient

Statement 2 states that
3l−k=3
Solving for k and plugging in, we get (3l - 3)*y = 2ly - 8
3ly - 3y = 2ly - 8
ly -3y = -8
y can be either 2 or 4
when y is 2, l = -1 and therefore k = -6. lk > 2
when y is 4, l = 1 and therefore k = 0 lk is not > 2

Re: If x and y belong to the set {2, 4}, and x^ky = x^(ly2−8), is kl > 2?   [#permalink] 22 Oct 2018, 16:29
Display posts from previous: Sort by