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

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach Starts Oct 17
Chris Peckover, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Chris Peckover, 100th-Percentile GMAT Scorer

Oct 17 · Chris Peckover
Sat · 11:00 AM to 2:00 PM ET
Oct 20 · Chris Peckover
Tue, Thu · 8:00 to 10:00 PM ET
Oct 25 · Josh Braslow
Sun · 1:00 to 4:00 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemand 5 seats left Start anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

Function data sufficiency

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |

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 » Mon Jul 28, 2014 2:50 am
alexandrabiorka wrote: Is f(x) < 0?

(1) f(x) = (x^3)^3(x^5)
(2) x = -2
Target question: Is f(x) less than 0?

Statement 1: f(x) = (x^3)^3(x^5)
Simplify to get: f(x) = (x^9)(x^5) = x^14
Since x is raised to an EVEN power, x^14 will be greater than or equal to zero for ANY x value.
If that's the case, then we can be certain that f(x) is NOT less than 0
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: x = -2
Here, we don't know anything about the function f(x)
Consider these two conflicting cases:
Case a: f(x) = x + 3, in which case f(-2) = -2 + 3 = 1. Here, f(x) is NOT less than 0
Case b: f(x) = x - 3, in which case f(-2) = -2 - 3 = -5. Here, f(x) IS less than 0
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer = A

Cheers,
Brent
Last edited by Brent@GMATPrepNow on Sat Oct 08, 2016 7:09 am, edited 1 time in total.
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 1100
Joined: Sat May 10, 2014 11:34 pmFollowed by: 24 members
Location: New Delhi, India
Thanked: 205 times

by GMATinsight » Mon Jul 28, 2014 8:23 am
alexandrabiorka wrote:Here is a data suffic problem I have been stumbling on.

Is f(x) < 0?

(1) f(x) = (x^3)^3(x^5)
(2) x=-2
Question : Is f(x) < 0?

Statement 1) f(x) = (x^3)^3(x^5)

Value of x is unknown, therefore,
INSUFFICIENT

Statement 2) x=-2

'How Function f(x) is related to x' is unknown therefore,
INSUFFICIENT

Combining the two statements
Both x and how f(x) is related to x are known, therefore
SUFFICIENT

Answer: Option C
"GMATinsight"Bhoopendra Singh & Sushma Jha
Most Comprehensive and Affordable Video Course 2000+ CONCEPT Videos and Video Solutions
Whatsapp/Mobile: +91-9999687183 l [email protected]
Contact for One-on-One FREE ONLINE DEMO Class Call/e-mail
Most Efficient and affordable One-On-One Private tutoring fee - US$40-50 per hour
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Newbie | Next Rank: 10 Posts
Posts: 7
Joined: Mon Apr 18, 2016 10:59 am

by dassabyasachi14 » Sat May 07, 2016 12:00 pm
Is f(x) < 0?

(1) f(x) = (x^3)^3(x^5)
(2) x=-2

I think the answer to this question is (A)- Statement (1) alone is sufficient.

Reason:
1) f(x)= x^14

So, if x=0==> f(x)=0

In this case, is f(x)<0?? ---> No, f(x)= 0

2) For x=-1==> f(x)= 1.

Again is f(x)<0?? ---> No

3) For x=1==> f(x)= 1.

Again is f(x)<0?? ---> No

All the previous answers to this question is (C).

Please clarify if my answer- "Statement (1) alone is sufficient" is incorrect??
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Newbie | Next Rank: 10 Posts
Posts: 2
Joined: Thu Aug 25, 2016 7:48 pm

by emilytay23 » Sun Aug 28, 2016 10:37 pm
I also think that it should indeed be A. Since the question asks Is f(x) < 0?

To which we can safely answer yes with the info in Statement 1. Since the exponent of 14 is even, it will never f(x) will never be negative.

Although the we dont know for sure what the value is f(x) is, the target question is phrased in a way that requires only a yes or no answer.

Please help!
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Newbie | Next Rank: 10 Posts
Posts: 4
Joined: Fri Oct 07, 2016 1:16 am
Thanked: 1 times

by harmeen19 » Sat Oct 08, 2016 2:18 am
Hi @Brent, I think the question stem says: "Is f(x)<0?" And not "Is f(x) greater than 0?" as mentioned in your response.

With this, Statement A: SUFFICIENT
Taking x=1, f(x) = (1)^14 = 1 , so answer to the question stem is NO
Taking x=0, f(x) = (0)^14 = 0 , so answer to the question stem is NO
We can answer the target question with certainty, so SUFFICIENT

Statement B: INSUFFICIENT since we dont know about the function f(x).

OA: a
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Newbie | Next Rank: 10 Posts
Posts: 4
Joined: Fri Oct 07, 2016 1:16 am
Thanked: 1 times

by harmeen19 » Sat Oct 08, 2016 2:23 am
Brent@GMATPrepNow wrote:
alexandrabiorka wrote: Is f(x) < 0?

(1) f(x) = (x^3)^3(x^5)
(2) x = -2
Target question: Is f(x) greater than 0?

Statement 1: f(x) = (x^3)^3(x^5)
Simplify to get: f(x) = (x^9)(x^5) = x^14
Since there are no restrictions on the value of x, there are several possible cases. Here are two:
Case a: x = 1, in which case f(x) = 1^14 = 1. In this case, f(x) is GREATER than 0
Case b: x = 0, in which case f(x) = 0^14 = 0. In this case, f(x) is NOT GREATER than 0
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: x = -2
Here, we don't know anything about the function f(x)
Consider these two conflicting cases:
Case a: f(x) = x + 3, in which case f(-2) = -2 + 3 = 1. Here, f(x) is GREATER than 0
Case b: f(x) = x - 3, in which case f(-2) = -2 - 3 = -5. Here, f(x) is NOT GREATER than 0
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
Statement 1 tells us that f(x) = x^14
Statement 2 tells us that x = -2
f(-2) = (-2)^14 = SOME POSITIVE VALUE
In other words, f(x) is definitely GREATER then 0
Since we can answer the target question with certainty, the combined statements are SUFFICIENT

Answer = C

Cheers,
Brent
Hi @Brent, I think the question stem says: "Is f(x)<0?" And not "Is f(x) greater than 0?" as mentioned in your response.

With this, Statement A: SUFFICIENT
Taking x=1, f(x) = (1)^14 = 1 , so answer to the question stem is NO
Taking x=0, f(x) = (0)^14 = 0 , so answer to the question stem is NO
We can answer the target question with certainty, so SUFFICIENT

Statement B: INSUFFICIENT since we dont know about the function f(x).

OA: a
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

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 » Sat Oct 08, 2016 7:11 am
harmeen19 wrote:Hi @Brent, I think the question stem says: "Is f(x)<0?" And not "Is f(x) greater than 0?" as mentioned in your response.

With this, Statement A: SUFFICIENT
Taking x=1, f(x) = (1)^14 = 1 , so answer to the question stem is NO
Taking x=0, f(x) = (0)^14 = 0 , so answer to the question stem is NO
We can answer the target question with certainty, so SUFFICIENT

Statement B: INSUFFICIENT since we dont know about the function f(x).

OA: a
You're absolutely right. I misread the question.
The correct answer is, indeed, A.
I have edited my response accordingly.

Cheers and thanks,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1