Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 47109

If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
21 Oct 2015, 21:46
Question Stats:
72% (01:20) correct 28% (01:38) wrong based on 1159 sessions
HideShow timer Statistics




Retired Moderator
Joined: 29 Apr 2015
Posts: 863
Location: Switzerland
Concentration: Economics, Finance
WE: Asset Management (Investment Banking)

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
23 Oct 2015, 00:35
Bunuel wrote: If a and b are positive integers, is a/b < 9/11 ?
(1) a/b = 0,818 (2) b/a = 1,223
Kudos for a correct solution. There is no need to calculate anything. We just need to know if we can ask the question: is a/b < 9/11? 1) a/b = 0,818 >> Sufficient. You know that you COULD get the exact result and figure out if a/b is < 9/11. You do not even have to ballpark, all you need to know is, that you COULD. Sufficient. 2) b/a = 1,223 >> Sufficient. The reciprocal would be a/b = 1/1,223, again, no need to calculate anything further, from this it is very clear that you can answer the question Y, or N. Answer D.
_________________
Saving was yesterday, heat up the gmatclub.forum's sentiment by spending KUDOS!
PS Please send me PM if I do not respond to your question within 24 hours.




SC Moderator
Joined: 13 Apr 2015
Posts: 1712
Location: India
Concentration: Strategy, General Management
GPA: 4
WE: Analyst (Retail)

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
22 Oct 2015, 00:08
9/11 = (9*9)/(11*9) = 0.8181 a/b < 0.8181 ?
or
11a < 9b > b/a > 11/9 > b/a > 1.22222 ?
St1: Sufficient St2: Sufficient
Answer: D



Manager
Joined: 02 Jul 2015
Posts: 106

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
22 Oct 2015, 04:30
The answer is D as
1. states that a/b=0.818 while stem states 0.818181...
2. 1/1223 is definitely smaller then 9/11



Manager
Joined: 02 Jul 2015
Posts: 106

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
23 Oct 2015, 00:50
reto wrote: Bunuel wrote: If a and b are positive integers, is a/b < 9/11 ?
(1) a/b = 0,818 (2) b/a = 1,223
Kudos for a correct solution. There is no need to calculate anything. We just need to know if we can ask the question: is a/b < 9/11? 1) a/b = 0,818 >> Sufficient. You know that you COULD get the exact result and figure out if a/b is < 9/11. You do not even have to ballpark, all you need to know is, that you COULD. Sufficient. 2) b/a = 1,223 >> Sufficient. The reciprocal would be a/b = 1/1,223, again, no need to calculate anything further, from this it is very clear that you can answer the question Y, or N. Answer D. retoIn retrospect I agree that DS merely asks if the information is enough or not. So no need to calculate.



Manager
Joined: 20 Mar 2015
Posts: 62

If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
03 Jul 2016, 10:29
St.1 \(\frac{a}{b}\) \(<\) \(\frac{9}{11}\) Sufficient. St.2 \(\frac{b}{a}\) \(>\) \(\frac{1223}{1000}\) Sufficient. Do we really need to calculate in this question? The answer will be either yes or no, but not both. The answer to any fraction, be it\(\frac{1000}{1224}\), \(\frac{1000}{1225}\) or any other will be different than \(\frac{9}{11}\). Abhishek009



Intern
Joined: 18 Nov 2014
Posts: 2

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
28 Jul 2016, 01:37
yes here it should be calculated



BSchool Forum Moderator
Joined: 12 Aug 2015
Posts: 2647

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
19 Nov 2016, 10:16
This is a great question from the Official guideHere is what i did we need to check whether a/b<9/11 or a/b<81/99 or a/b<0.8181818181818181.. Statement 1 a/b<0.818 hmm Since 0.818<0.8181818181.. Hence a/b<9/11 Hence Sufficient Statement 2 Here a/b<1000/1223 Hence a/b<0.817something Hence a/b<0.8181818 Hence Sufficient I have a question Can we solve it without solving the statement 2? I mean without performing the long division Any tricks @cheetan2u ? Regards Stone Cold
_________________
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!



Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 3647
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)

If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
20 Nov 2016, 03:25
Bunuel wrote: If a and b are positive integers, is a/b < 9/11 ?
(1) a/b < 0.818 (2) b/a > 1.223
Kudos for a correct solution. FROM STATEMENT  I ( SUFFICIENT )\(\frac{a}{b} < \frac{818}{1000}\) Or, \(\frac{a}{b} < 81.8\) % Now, \(\frac{9}{11} = 81.8\) % Thus , \(\frac{a}{b}\) < \(\frac{9}{11}\) FROM STATEMENT  II ( SUFFICIENT )\(\frac{b}{a} > 1.223\) so, \(b = 1223\) and \(a = 1000\) Hence, \(\frac{a}{b} = 81.77\) % So, EACH statement ALONE is sufficient to answer the question asked, answer will be (D)
_________________
Thanks and Regards
Abhishek....
PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS
How to use Search Function in GMAT Club  Rules for Posting in QA forum  Writing Mathematical Formulas Rules for Posting in VA forum  Request Expert's Reply ( VA Forum Only )



Senior Manager
Joined: 08 Dec 2015
Posts: 302

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
27 Dec 2016, 12:23
Guys could you post a compilation of these exotic rules for fractions? like that the number of 9's in the denominator defines the number of repeating decimals, etc?? Thank you!



Manager
Joined: 13 Dec 2013
Posts: 161
Location: United States (NY)
Concentration: Nonprofit, International Business
GMAT 1: 710 Q46 V41 GMAT 2: 720 Q48 V40
GPA: 4
WE: Consulting (Consulting)

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
16 Mar 2017, 13:01
Bunuel wrote: GinGMAT wrote: The statements here are posted incorrectly (this question is in GMAC OG 2016). Statement 1 is a/b < 0.818 and statement 2 is b/a > 1.223. So you do need to do calculations since it is not an equal sign. You are right. Edited. Thank you. Even with the inequalities, do we need to calculate here?



Senior Manager
Joined: 08 Dec 2015
Posts: 302

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
01 Jul 2017, 05:29
And how is it possible to answer "without calculation"??? We are given a range so it can be yes or no, you have to be sure!



Manager
Joined: 21 Oct 2017
Posts: 70
Location: Canada
Concentration: Entrepreneurship, Technology
WE: Project Management (Internet and New Media)

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
23 Nov 2017, 18:28
Same question as people above. This question is really easy with a calculator. A little less so without it, under stress and under 2 minutes. Anyone willing to break down the mental math on this one? Because clearly approximation wither an option here. Thanks, Posted from my mobile device
_________________
Please Press +1 Kudos if it helps!
October 9th, 2017: Diagnostic Exam  Admit Master (GoGMAT)  640 November 11th, 2017: CAT 1  Admit Master (GoGMAT)  700 November 20th, 2017: CAT 2  GMATPrep  700 (Q: 47, V: 40) November 25th, 2017: CAT 3  Admit Master (GoGMAT)  710 (Q: 48, V: 40) November 27th, 2017: CAT 4  GMATPrep  720 (Q: 49, V: 40)
December 4th, 2017: GMAT Exam  750 (Q: 48, V: 44, IR: 8, AWA: 6)



DS Forum Moderator
Joined: 22 Aug 2013
Posts: 1282
Location: India

If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
23 Nov 2017, 23:35
Hadrienlbb wrote: Same question as people above. This question is really easy with a calculator. A little less so without it, under stress and under 2 minutes.
Anyone willing to break down the mental math on this one? Because clearly approximation wither an option here.
Thanks,
Posted from my mobile device Hi Knowing the fractions to decimal conversions would help here. Eg: 1/2 = 0.5, 1/3 = 0.333.., 1/4 = 0.25, 1/5 = 0.2, 1/6 = 0.1666.., 1/7 = 0.1428.., 1/8 = 0.125, 1/9 = 0.1111.., 1/10 = 0.1, 1/11 = 0.090909.., 1/12 = 0.08333.., and so on. Its good to practice writing these from 1/2 to 1/20 often, because this could help you in various questions. Here in this question if we remember that 1/11 = 0.090909.. we would know that 9/11 = 9*0.090909.. = 0.818181..



Manager
Joined: 21 Oct 2017
Posts: 70
Location: Canada
Concentration: Entrepreneurship, Technology
WE: Project Management (Internet and New Media)

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
24 Nov 2017, 09:20
amanvermagmat wrote: Hadrienlbb wrote: Same question as people above. This question is really easy with a calculator. A little less so without it, under stress and under 2 minutes.
Anyone willing to break down the mental math on this one? Because clearly approximation wither an option here.
Thanks,
Posted from my mobile device Hi Knowing the fractions to decimal conversions would help here. Eg: 1/2 = 0.5, 1/3 = 0.333.., 1/4 = 0.25, 1/5 = 0.2, 1/6 = 0.1666.., 1/7 = 0.1428.., 1/8 = 0.125, 1/9 = 0.1111.., 1/10 = 0.1, 1/11 = 0.90909.., 1/12 = 0.8333.., and so on. Its good to practice writing these from 1/2 to 1/20 often, because this could help you in various questions. Here in this question if we remember that 1/11 = 0.90909.. we would know that 9/11 = 9*0.90909.. = 0.818181.. I actually tried that. I have a formula sheet with fractions/decimals/percents up to 12. So 1/9 = 0.111 and 1/11 = 0.0909 But again, going from 1/11 = 0.0909 to 9/11 = 0.8181 isn't exactly natural for me, unfortunately. I need to write down the multiplication/division, and that usually leads me to exceed the 2minute mark.
_________________
Please Press +1 Kudos if it helps!
October 9th, 2017: Diagnostic Exam  Admit Master (GoGMAT)  640 November 11th, 2017: CAT 1  Admit Master (GoGMAT)  700 November 20th, 2017: CAT 2  GMATPrep  700 (Q: 47, V: 40) November 25th, 2017: CAT 3  Admit Master (GoGMAT)  710 (Q: 48, V: 40) November 27th, 2017: CAT 4  GMATPrep  720 (Q: 49, V: 40)
December 4th, 2017: GMAT Exam  750 (Q: 48, V: 44, IR: 8, AWA: 6)



Intern
Joined: 13 Jan 2018
Posts: 2

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
27 Feb 2018, 11:33
b/a = 1.2222222222 this rounded makes 1.223, I don't think D is the right answer



DS Forum Moderator
Joined: 22 Aug 2013
Posts: 1282
Location: India

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
27 Feb 2018, 22:31
AjayRawtani wrote: b/a = 1.2222222222 this rounded makes 1.223, I don't think D is the right answer Hi First of all 1.2222222.. if rounded to thousandth decimal place, does NOT become 1.223, rather it becomes 1.222 (because the digit after that is '2' which is less than 5) And secondly, we simply dont need to do rounding off here. The second statement tells us that: b/a > 1.223 So anything which is greater than 1.223 will obviously also be greater than 1.2222222 (because 1.223 itself is greater than 1.2222222...). Thus we are getting the answer



Intern
Joined: 21 Sep 2012
Posts: 3

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
27 Feb 2018, 23:04
amanvermagmat wrote: AjayRawtani wrote: b/a = 1.2222222222 this rounded makes 1.223, I don't think D is the right answer Hi First of all 1.2222222.. if rounded to thousandth decimal place, does NOT become 1.223, rather it becomes 1.222 (because the digit after that is '2' which is less than 5) And secondly, we simply dont need to do rounding off here. The second statement tells us that: b/a > 1.223 So anything which is greater than 1.223 will obviously also be greater than 1.2222222 (because 1.223 itself is greater than 1.2222222...). Thus we are getting the answer My bad I made a silly mistake, In my head I had the question and option B mixed up. I really need to work on cutting down silly mistakes. Sent from my ONEPLUS A3003 using GMAT Club Forum mobile app



Intern
Joined: 29 Oct 2016
Posts: 1

Re: If a and b are positive integers, is a/b < 9/11 ? [#permalink]
Show Tags
01 Jul 2018, 22:30
reto wrote: Bunuel wrote: If a and b are positive integers, is a/b < 9/11 ?
(1) a/b = 0,818 (2) b/a = 1,223
Kudos for a correct solution. There is no need to calculate anything. We just need to know if we can ask the question: is a/b < 9/11? 1) a/b = 0,818 >> Sufficient. You know that you COULD get the exact result and figure out if a/b is < 9/11. You do not even have to ballpark, all you need to know is, that you COULD. Sufficient. 2) b/a = 1,223 >> Sufficient. The reciprocal would be a/b = 1/1,223, again, no need to calculate anything further, from this it is very clear that you can answer the question Y, or N. Answer D. Hello, many thanks for this answer. What would be the right and the fastest way to get to the right answer if we did not use the equal signs but "<" and ">" signs as in the original question? Would we still do NOT have to calculate? " If a and b are positive integers, is a/b < 9/11 ? (1) a/b < 0.818 (2) b/a > 1.223 " Thank you! Have a nice day Aleks




Re: If a and b are positive integers, is a/b < 9/11 ?
[#permalink]
01 Jul 2018, 22:30






