BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

GMAT Prep Test 2 - Problem Solving

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 8
Joined: Thu Dec 06, 2012 7:12 amFollowed by: 1 member
Thanked: 1 times
by v_schame » Tue Jan 29, 2013 2:48 pm
Hi,

I did test prep 2 and I can't seem to get to the right answer. I tried several things, but I'm not sure I'm 100% of the f(x)=f(x-1) -> does this mean to replace the x values in each equation with x-1?

For which of the following functions f is f(x)=f(1-x) for all x?

A - f(x)=1-x
B - f(x)=1-x^2
C - f(x)=x^2-(1-x)^2
D - f(x)=x^2(1-x)^2
E - f(x)=x/(1-x)

The correct answer is d).

Thanks!

V
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Tue Jan 29, 2013 3:23 pm
v_schame wrote: For which of the following functions f is f(x)=f(1-x) for all x?

A - f(x)=1-x
B - f(x)=1-x^2
C - f(x)=x^2-(1-x)^2
D - f(x)=x^2(1-x)^2
E - f(x)=x/(1-x)
Let's try plugging in an easy value for x. How about x = 0.
So, we can reword the question as, For which of the following functions is f(0)=f(1-0)
In other words, we're looking for a function such that f(0) = f(1)

A) f(x)=1-x
f(0)=1-0 = 1
f(1)=1-1 = 0
Since f(0) doesn't equal f(1), eliminate A

B) f(x) = 1 - x^2
f(0) = 1 - 0^2 = 1
f(1) = 1 - 1^2 = 0
Since f(0) doesn't equal f(1), eliminate B

C) f(x) = x^2 - (1-x)^2
f(0) = 0^2 - (1-0)^2 = -1
f(1) = 1^2 - (1-1)^2 = 1
Since f(0) doesn't equal f(1), eliminate C

D) f(x) = x^2(1-x)^2
f(0) = 0^2(1-0)^2 = 0
f(1) = 1^2(1-1)^2 = 0
Since f(0) equals f(1), keep D for now

E) f(x) = x/(1-x)
f(0) = 0/(1-0) = 0
f(1) = 1/(1-1) = undefined
Since f(0) doesn't equal f(1), eliminate E

Since only D satisfies the condition that f(x)=f(1-x) when x=0, the correct answer is D

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 298
Joined: Sun Jun 03, 2012 6:42 amFollowed by: 7 members
Location: New delhi
Thanked: 10 times
GMAT Score:590

by varun289 » Fri Feb 01, 2013 10:56 am
v_schame wrote:
For which of the following functions f is f(x)=f(1-x) for all x?

A - f(x)=1-x
B - f(x)=1-x^2
C - f(x)=x^2-(1-x)^2
D - f(x)=x^2(1-x)^2
E - f(x)=x/(1-x)
these type questions are simple but thought - create illusions
put x=1-x in FX u get x=1-x so leave that , A gone
B- (1-x)^2 = make lots of wordy , leave that
c- another wordy forget
D-yes put X =1-x u get same figure as (1-x)^2X^2
Click and move on

simple coollll
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1