GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 14 Dec 2018, 04:27

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel
Events & Promotions in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar

The ratio of the ages of A and B is 7 : 11. Which of the following can

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51214
The ratio of the ages of A and B is 7 : 11. Which of the following can  [#permalink]

Show Tags

New post 30 Jun 2017, 02:21
1
6
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

70% (02:02) correct 30% (02:20) wrong based on 126 sessions

HideShow timer Statistics

The ratio of the ages of A and B is 7 : 11. Which of the following can be the ratio of their ages after 5 years?

(A) 1 : 3
(B) 9 : 20
(C) 4 : 15
(D) 3 : 5
(E) 2 : 3

_________________

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?
Extra-hard Quant Tests with Brilliant Analytics

Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 7106
Re: The ratio of the ages of A and B is 7 : 11. Which of the following can  [#permalink]

Show Tags

New post 30 Jun 2017, 07:43
3
Bunuel wrote:
The ratio of the ages of A and B is 7 : 11. Which of the following cannot be the ratio of their ages after 5 years?

(A) 1 : 3
(B) 9 : 20
(C) 4 : 15
(D) 3 : 5
(E) 2 : 3


hi Bunuel,

seems there is a typo. i think it should be can and not cannot..

if the Q says can be, the logic to get the answer immediately without any trial is..
Ratio is \(\frac{7}{11}\) or the numbers are \(\frac{7x}{11x}\), so if you are adding SAME amount to both denominator and numerator, the value of RATIO will INCREASE

A,B,C are LESS than 7/11 in first look ..
D. 3/5 .. it is close so check 3/5 , 7/11.....\(\frac{3*11 , 7*5}{55}\)...
35>33 so 7/11>3/5

remaining E is the answer..
when x is 5..\(\frac{7x}{11x} = \frac{35}{55}\)..
add 5 to both ages \(\frac{35+5}{55+5}=\frac{40}{60}=\frac{2}{3}\)

E
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

Board of Directors
User avatar
P
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4276
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User Premium Member CAT Tests
Re: The ratio of the ages of A and B is 7 : 11. Which of the following can  [#permalink]

Show Tags

New post 30 Jun 2017, 08:08
2
Bunuel wrote:
The ratio of the ages of A and B is 7 : 11. Which of the following cannot be the ratio of their ages after 5 years?

(A) 1 : 3
(B) 9 : 20
(C) 4 : 15
(D) 3 : 5
(E) 2 : 3

With chetan2u
Attachment:
Capture.PNG
Capture.PNG [ 7.23 KiB | Viewed 1717 times ]

IMHO with (E)
_________________

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 )

Intern
Intern
avatar
B
Joined: 01 May 2017
Posts: 30
Re: The ratio of the ages of A and B is 7 : 11. Which of the following can  [#permalink]

Show Tags

New post 30 Jun 2017, 08:12
2
1
Adding the same number to the numerator and denominator of a ratio causes the resultant ratio to move closer to "1".

Eg: Consider 1/2 (0.5) which is lesser than 1. Suppose we add 2 to both numerator and denominator. Final ration = 3/4 (0.75) -> closer to 1.
Now consider 3/2 (1.5) which is greater than one 1. Suppose we add 2 to both numerator and denominator. Final ration = 5/4 (1.25) -> closer to 1.

Using the same logic for solving the above question,
7/11 = 0.6363

after 5 years,
[(7x + 5)/ (11x + 5)] >0.6363 (adding 5 to both numerator and denominator should cause the final value to move closer to 1)

I agree with Chetan2u - there is a typo probably - should be "can" and not "cannot"

(A) 1 : 3 = 0.33
(B) 9 : 20 = 0.45
(C) 4 : 15 = 0.26
(D) 3 : 5 = 0.60
(E) 2 : 3 = 0.66 => Ans
Intern
Intern
avatar
Joined: 28 Jun 2017
Posts: 7
Re: The ratio of the ages of A and B is 7 : 11. Which of the following can  [#permalink]

Show Tags

New post 30 Jun 2017, 08:30
4
After 5 years the ratio of their ages MUST be higher than what it is now (since same value is being added to both numerator and denominator). Therefore only valid option is Option (E).
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51214
Re: The ratio of the ages of A and B is 7 : 11. Which of the following can  [#permalink]

Show Tags

New post 01 Jul 2017, 05:36
Target Test Prep Representative
User avatar
P
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4294
Location: United States (CA)
Re: The ratio of the ages of A and B is 7 : 11. Which of the following can  [#permalink]

Show Tags

New post 04 Jul 2017, 07:14
2
1
Bunuel wrote:
The ratio of the ages of A and B is 7 : 11. Which of the following can be the ratio of their ages after 5 years?

(A) 1 : 3
(B) 9 : 20
(C) 4 : 15
(D) 3 : 5
(E) 2 : 3


We may recall the rule that if any ratio a/b, in which a is less than b, and a positive constant is added to both the numerator and denominator of the fraction, then the resulting fraction is greater than the original one.

We see that 7/11 is around 0.63, and since 2/3 = 0.667, we see that 2/3 is the only ratio that is larger than 0.63.

Answer: E
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 9159
Premium Member
Re: The ratio of the ages of A and B is 7 : 11. Which of the following can  [#permalink]

Show Tags

New post 16 Aug 2018, 12:07
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

GMAT Club Bot
Re: The ratio of the ages of A and B is 7 : 11. Which of the following can &nbs [#permalink] 16 Aug 2018, 12:07
Display posts from previous: Sort by

The ratio of the ages of A and B is 7 : 11. Which of the following can

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.