Author 
Message 
TAGS:

Hide Tags

Director
Status: My Thread Master Bschool Threads>Krannert(Purdue),WP Carey(Arizona),Foster(Uwashngton)
Joined: 28 Jun 2011
Posts: 830

Re: cube root of (89)
[#permalink]
Show Tags
27 Jun 2013, 01:08
Bunuel wrote: tejal777 wrote: The value of cube root of (89) is..? Between 9 and 10 Between 8 and 9 Between 4 and 5 Between 3 and 4 Undefined ................... Is'nt the root of any negative number undefined? Even roots from negative number is undefined on the GMAT (as GMAT is dealing only with Real Numbers): \(\sqrt[{even}]{negative}=undefined\), for example \(\sqrt{25}=undefined\). Odd roots will have the same sign as the base of the root. For example, \(\sqrt[3]{125} =5\) and \(\sqrt[3]{64} =4\). The above question is quite tricky: \(\sqrt[3]{89}\) is more than 5 (as \(5^3=125\)) but less than 4 (as \(4^3=64\)) > \(5<x<4\), (actually it's \(\approx{4.5}\)). So the the range would be between 5 and 4. The only answer choice to cover this range is A (9, 10). Answer: A. Concept was easy, messed up with the options.. 5 and 4 wll be only covered in option A



Manager
Joined: 30 Mar 2013
Posts: 112

Re: The value of cube root of (89) is:
[#permalink]
Show Tags
26 Nov 2014, 11:41
jcurry wrote: \(\sqrt[3]{89}\) is:
A) Between 9 and 10 B) Between 8 and 9 C) Between 4 and 5 D) Between 3 and 4 E) Undefined
My guess (D) was incorrect because I guess I did \(\sqrt[4]{81}= 3\) and \(\sqrt[3]{64}= 4\) Should be C. I'd take the ve outside, and since \(\(4)^3\) = 64 and \(\(5)^3\) = 125, the answer just lies somewhere between these two, therefore C. Please note that this is a slightly different question than the first question asked in this thread.



SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1834
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)

The value of cube root of (89) is:
[#permalink]
Show Tags
27 Nov 2014, 19:05
\((4)^3 = 64\) \((5)^3 = 125\) If a number line is drawn, the cube root would lie between 4 & 5 10...... 9.......... 8.......... 7............ 6..... 5........................ 4 ...... 3...... 2... 1.......... 0..... 1..... 2..... 3...... 4....... 5....... 6........ 7....... 8....... 9.......... 10 Its very clear looking at the number line, answer = A
_________________
Kindly press "+1 Kudos" to appreciate



Current Student
Status: Applied
Joined: 02 May 2014
Posts: 152
Location: India
Concentration: Operations, General Management
Schools: Tulane '18 (A), Tippie '18 (D), Moore '18, Katz '18 (D), UCSD '18, Madison '18, Olin '18 (S), Simon '18, Desautels '18 (I), Sauder '18 (S), Terry '18 (WL), GWU '18, Neeley '18 (WL), Weatherhead '18 (S), Fox(Temple)'18, Eller FT'18 (A), Schulich Sept"18 (S)
GPA: 3.35
WE: Information Technology (Computer Software)

The value of cube root of (89) is:
[#permalink]
Show Tags
28 Nov 2014, 09:15
tejal777 wrote: The value of cube root of (89) is:
A. Between 9 and 10 B. Between 8 and 9 C. Between 4 and 5 D. Between 3 and 4 E. Undefined The answer to this question is tricky...have to be careful while finding the answer...ans lies between 4 and 5 and option A is the only option that includes this range. Thanks for the question.



Current Student
Joined: 30 Dec 2015
Posts: 188
Location: United States
Concentration: Strategy, Organizational Behavior
GPA: 3.88
WE: Business Development (Hospitality and Tourism)

Re: The value of cube root of (89) is:
[#permalink]
Show Tags
29 Jan 2016, 06:42
Bunuel wrote: tejal777 wrote: The value of cube root of (89) is..? Between 9 and 10 Between 8 and 9 Between 4 and 5 Between 3 and 4 Undefined ................... Is'nt the root of any negative number undefined? Even roots from negative number is undefined on the GMAT (as GMAT is dealing only with Real Numbers): \(\sqrt[{even}]{negative}=undefined\), for example \(\sqrt{25}=undefined\). Odd roots will have the same sign as the base of the root. For example, \(\sqrt[3]{125} =5\) and \(\sqrt[3]{64} =4\). The above question is quite tricky: \(\sqrt[3]{89}\) is more than 5 (as \(5^3=125\)) but less than 4 (as \(4^3=64\)) > \(5<x<4\), (actually it's \(\approx{4.5}\)). So the the range would be between 5 and 4. The only answer choice to cover this range is A (9, 10). Answer: A. Hi! Can you explain this: So the the range would be between 5 and 4. The only answer choice to cover this range is A (9, 10). ? I don't understand it. Thank you.



Math Expert
Joined: 02 Sep 2009
Posts: 49300

Re: The value of cube root of (89) is:
[#permalink]
Show Tags
29 Jan 2016, 06:56
lpetroski wrote: Bunuel wrote: tejal777 wrote: The value of cube root of (89) is..? Between 9 and 10 Between 8 and 9 Between 4 and 5 Between 3 and 4 Undefined ................... Is'nt the root of any negative number undefined? Even roots from negative number is undefined on the GMAT (as GMAT is dealing only with Real Numbers): \(\sqrt[{even}]{negative}=undefined\), for example \(\sqrt{25}=undefined\). Odd roots will have the same sign as the base of the root. For example, \(\sqrt[3]{125} =5\) and \(\sqrt[3]{64} =4\). The above question is quite tricky: \(\sqrt[3]{89}\) is more than 5 (as \(5^3=125\)) but less than 4 (as \(4^3=64\)) > \(5<x<4\), (actually it's \(\approx{4.5}\)). So the the range would be between 5 and 4. The only answer choice to cover this range is A (9, 10). Answer: A. Hi! Can you explain this: So the the range would be between 5 and 4. The only answer choice to cover this range is A (9, 10). ? I don't understand it. Thank you. The question asks about the range the cube root of (89) is. We found that it's between 5 and 4, approximately 4.5. Now, can you tell me in which range from the options given is 4.5?
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Manager
Status: One Last Shot !!!
Joined: 04 May 2014
Posts: 241
Location: India
Concentration: Marketing, Social Entrepreneurship
GMAT 1: 630 Q44 V32 GMAT 2: 680 Q47 V35

Re: The value of cube root of (89) is:
[#permalink]
Show Tags
30 Nov 2016, 19:43
BTW, i noticed that the range given in option A 9 to +10, is the widest of all and covers all other ranges in the options. So, whatever falls in other ranges, will fall in this range. And this is an official question. So, on the real test, why cant i just mark option A blindly and move on? also, since no two options can be correct, option A has to win.
_________________
One Kudos for an everlasting piece of knowledge is not a bad deal at all...
 Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover. Mark Twain



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 8284
Location: Pune, India

Re: The value of cube root of (89) is:
[#permalink]
Show Tags
30 Nov 2016, 23:45
arhumsid wrote: BTW, i noticed that the range given in option A 9 to +10, is the widest of all and covers all other ranges in the options. So, whatever falls in other ranges, will fall in this range. And this is an official question. So, on the real test, why cant i just mark option A blindly and move on?
also, since no two options can be correct, option A has to win. Yes, if it is defined, it will certainly lie in the range 9 and 10 since it covers all other ranges. So answer would be (A).
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >
GMAT selfstudy has never been more personalized or more fun. Try ORION Free!



Current Student
Joined: 12 Aug 2015
Posts: 2648

Re: The value of cube root of (89) is:
[#permalink]
Show Tags
18 Jun 2017, 05:39
Excellent Official Question. Here is what I did on this one > Let m= (84)^1/3 m^3 = 84 Hence m => (5,4) Only bound that satisfies is A. NOTE > C is a BIG trap as within the time constraint we might end up choosing C.
_________________
MBA Financing: INDIAN PUBLIC BANKS vs PRODIGY FINANCE! Getting into HOLLYWOOD with an MBA! The MOST AFFORDABLE MBA programs!STONECOLD's BRUTAL Mock Tests for GMATQuant(700+)AVERAGE GRE Scores At The Top Business Schools!



Director
Joined: 17 Dec 2012
Posts: 636
Location: India

Re: The value of cube root of (89) is:
[#permalink]
Show Tags
08 Mar 2018, 18:12
tejal777 wrote: The value of cube root of (89) is:
A. Between 9 and 10 B. Between 8 and 9 C. Between 4 and 5 D. Between 3 and 4 E. Undefined Main idea: The cube root should be within the range even though the range may be large Details: Cube root of 89 is between 4 and 5. This is only in the range given in choice A .
_________________
Srinivasan Vaidyaraman Sravna Holistic Solutions http://www.sravnatestprep.com
Holistic and Systematic Approach



Intern
Joined: 20 Dec 2017
Posts: 34

Re: The value of cube root of (89) is:
[#permalink]
Show Tags
08 Mar 2018, 20:04
This is a question that tests if you know the the basics well:
There are 2 parts to this:
1) Is it a Negative or Positive Integer? A negative cube root integer will result in a negative integer. Similarly, a cubed negative integer will result in a another negative integer. i.e. \(3^3 = 9\) and viceversa
For this question, the answer must be in the negative region
2) What is the absolute value of the answer \(4^3 = 64\) & \(5^3 = 125\)
For this question, the answer must somehow involve \(4^3\) & \(5^3\)
Putting (1) & (2) together,
The answer is between 4 & 5. Hence (A)




Re: The value of cube root of (89) is: &nbs
[#permalink]
08 Mar 2018, 20:04



Go to page
Previous
1 2
[ 31 posts ]



