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

 It is currently 19 Oct 2019, 05:46

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

Find an interval I on which

Author Message
Senior Manager
Joined: 10 Apr 2018
Posts: 266
Location: United States (NC)
Find an interval I on which  [#permalink]

Show Tags

15 Sep 2018, 16:55
00:00

Difficulty:

(N/A)

Question Stats:

50% (01:54) correct 50% (01:44) wrong based on 2 sessions

HideShow timer Statistics

Find an interval I on which a < b implies a$$e^{−a}$$ > b$$e^{−b}$$, where $$e$$ is mathematical constant approximately equal to 2.71

(A) (1, $$\infty$$ )
(B) [1, $$\infty$$ ]
(C) (- $$\infty$$ ,0 ]
(D) (- $$\infty$$ ,0 )
(E) (-$$\infty$$, $$\infty$$ )

_________________
Probus

~You Just Can't beat the person who never gives up~ Babe Ruth
SC Moderator
Status: GMAT - Pulling Quant and Verbal together
Joined: 04 Sep 2017
Posts: 237
Location: United States (OH)
GPA: 3.6
WE: Sales (Computer Software)
Re: Find an interval I on which  [#permalink]

Show Tags

15 Sep 2018, 19:19
1
Probus wrote:
Find an interval I on which a < b implies a$$e^{−a}$$ > b$$e^{−b}$$, where $$e$$ is mathematical constant approximately equal to 2.71

(A) (1, $$\infty$$ )
(B) [1, $$\infty$$ ]
(C) (- $$\infty$$ ,0 ]
(D) (- $$\infty$$ ,0 )
(E) (-$$\infty$$, $$\infty$$ )

I'm pretty sure the GMAT does not test the difference between ) and ]

I changed e to = 3 for the sake of easy numbers.

3a^(-a) > ab^-b and a < b

I first tested to see if a could be less than 1 and I used -3. Then made b = -2

$$-9^3$$ > $$-6^2$$

This does not work.

Now try a >1 and b > a

Make a = 2 and b = 3

$$\frac{1}{6}$$ > $$\frac{1}{9}$$

This works

_________________
Would I rather be feared or loved? Easy. Both. I want people to be afraid of how much they love me.

How to sort questions by Topic, Difficulty, and Source:
https://gmatclub.com/forum/search.php?view=search_tags
Re: Find an interval I on which   [#permalink] 15 Sep 2018, 19:19
Display posts from previous: Sort by