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

 It is currently 15 Dec 2019, 17:07

### 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 f(x) = 10x/(1 − x), for what value of x does f (x) = 1/2*f(3)?

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 59730
If f(x) = 10x/(1 − x), for what value of x does f (x) = 1/2*f(3)?  [#permalink]

### Show Tags

01 Oct 2018, 23:13
00:00

Difficulty:

15% (low)

Question Stats:

88% (01:54) correct 13% (01:58) wrong based on 46 sessions

### HideShow timer Statistics

If f(x) = 10x/(1 − x), for what value of x does f (x) = 1/2*f(3)?

(A) 4
(B) 2
(C) 1
(D) -3
(E) -5

_________________
RC Moderator
Joined: 24 Aug 2016
Posts: 782
GMAT 1: 540 Q49 V16
GMAT 2: 680 Q49 V33
Re: If f(x) = 10x/(1 − x), for what value of x does f (x) = 1/2*f(3)?  [#permalink]

### Show Tags

01 Oct 2018, 23:29
1
Bunuel wrote:
If f(x) = 10x/(1 − x), for what value of x does f (x) = 1/2*f(3)?

(A) 4
(B) 2
(C) 1
(D) -3
(E) -5

f(x) = 10x/(1 − x) or f(3) = 10*3/(1 − 3)= -15
hence , 10x/(1 − x)=1/2*(-15) ===> x=-3 Ans D
_________________
Please let me know if I am going in wrong direction.
Thanks in appreciation.
NUS School Moderator
Joined: 18 Jul 2018
Posts: 1027
Location: India
Concentration: Finance, Marketing
WE: Engineering (Energy and Utilities)
Re: If f(x) = 10x/(1 − x), for what value of x does f (x) = 1/2*f(3)?  [#permalink]

### Show Tags

01 Oct 2018, 23:33
f(3) = 10*3/(1-3) = 30/-2 = -15

If x = -3, then

f(-3) = -30/(1+3) = -30/4 = -15/2 = 1/2f(3)

Re: If f(x) = 10x/(1 − x), for what value of x does f (x) = 1/2*f(3)?   [#permalink] 01 Oct 2018, 23:33
Display posts from previous: Sort by