1) INSUFFICIENT - you will not know if x is positive or negative.
2) INSUFFICIENT - could be any negative number and some positive numbers.
Answer C, x would equal roughly -20.5, which would mean you can calculate x^5. 1 gives you two numbers to choose from and 2 tells you it is negative.
BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course
Redeem
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
x^5 ?
Source: Beat The GMAT — Data Sufficiency |
-
Jim@StratusPrep
- MBA Admissions Consultant
- Posts: 2279
- Location: New York
- Thanked: 660 times
- GMAT Score:770
GMAT Answers provides a world class adaptive learning platform.
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review
Hi Jim, Thanks for your explanation. How did you calculate -20.5 for x? And 2) x^9 < any number less then 23 would satisfy the answer C, right? And then If 2) x^9 < 24, the answer could not be C? I am a little bit confused about 23.
st(1) implies x=|sqrt(426)| which is Not Sufficientdreamv wrote:What is value of X^5?
1)X^2=426
2)X^9 < 23
st(2) implies x can be assigned any value to the left of 23^(5/9) Not Sufficient
Only combining st(1&2) is Sufficient and you don't need to calculate the exact values like -20.5 or -20.65 to answer this question, because this is DS type of question which requires sufficiency test only.
c
Success doesn't come overnight!
when two statements are combined their jointly assigned values are considered, from st(1) x=-sqrt(426) and from st(2) x^5<23^(5/9) and not x^9 < 24, because the powers are different in your doubt.dreamv wrote:Hi Jim, Thanks for your explanation. How did you calculate -20.5 for x? And 2) x^9 < any number less then 23 would satisfy the answer C, right? And then If 2) x^9 < 24, the answer could not be C? I am a little bit confused about 23.
Success doesn't come overnight!
-
[email protected]
- Legendary Member
- Posts: 934
- Location: AAMCHI MUMBAI LOCAL
- Thanked: 63 times
really a good sum to entertain...
IT IS TIME TO BEAT THE GMAT
LEARNING, APPLICATION AND TIMING IS THE FACT OF GMAT AND LIFE AS WELL... KEEP PLAYING!!!
Whenever you feel that my post really helped you to learn something new, please press on the 'THANK' button.
LEARNING, APPLICATION AND TIMING IS THE FACT OF GMAT AND LIFE AS WELL... KEEP PLAYING!!!
Whenever you feel that my post really helped you to learn something new, please press on the 'THANK' button.
This is one of those rare cases where DS actually saves us some trouble...in this case we don't actually have to calculate anything!pappueshwar wrote:hello every one,
i am confused as to how C is the answer..
can any one provide a better way
The key to this problem is knowing the following:
x^2 = 25 is NOT the same thing as x = sqrt(25)
This is because both 5*5 = 25 AND -5*-5 = 25, which both work for x^2 = 25
So from part (1), we are able to narrow down the answer for x to two possibilities:
+sqrt(426)
OR
-sqrt(426)
Now, if the case statement were to determine x^4 or x^6 or any other even power, the answer would be A, because any number to an even power is positive, regardless of its sign (in this case + or - sqrt(426). But the question is to find x^5, which can be two different values, based on part (1) alone.
From part (2), we are told that x^9 < 23.
Obviously the makers of the GMAT don't want us wasting time raising a number like sqrt(426) to the power of 9, so there must be another reason they are giving us this bit of info...
Clearly, part 2 alone is INSUFFICIENT, since there are infinite values of x that can give us a value for x^9 less than 23 (fractions and negative numbers especially).
Combining parts (1) and (2):
The real reason they are giving us part 2 becomes evident when joining together both parts: they are telling us that x is less than 23. From part (1), we know that the negative possibility is less than 23, but what about the possitive possibility??
Since the sqrt(426)^2 is 426, which is MUCH larger than 23, we can safely assume that x^9 is also larger than 23.
Therefore, only -sqrt(426) will work for x, which will allow for one, distinct answer for x^5. No messy calculations needed.
C
