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

It is currently 16 Dec 2018, 18:51

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
  • 10 Keys to nail DS and CR questions

     December 17, 2018

     December 17, 2018

     06:00 PM PST

     07:00 PM PST

    Join our live webinar and learn how to approach Data Sufficiency and Critical Reasoning problems, how to identify the best way to solve each question and what most people do wrong.
  • FREE Quant Workshop by e-GMAT!

     December 16, 2018

     December 16, 2018

     07:00 AM PST

     09:00 AM PST

    Get personalized insights on how to achieve your Target Quant Score.

If k is a 3 digit positive number, what is the hundred digit

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

Hide Tags

Manager
Manager
avatar
Joined: 07 Feb 2010
Posts: 129
If k is a 3 digit positive number, what is the hundred digit  [#permalink]

Show Tags

New post 09 Nov 2010, 05:19
2
11
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

60% (02:18) correct 40% (01:56) wrong based on 403 sessions

HideShow timer Statistics

If k is a 3 digit positive number, what is the hundred digit of k?

(1) The hundred digit of k+150 is 4
(2) The tens digit of k+25 is 7
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51229
Re: if k is a 3 digit positive number  [#permalink]

Show Tags

New post 09 Nov 2010, 05:29
5
7
If k is a positive three-digit integer, what is the hundreds digit of k?

(1) The hundreds digit of K +150 is 4 --> \(400\leq{k+150}\leq{499}\) --> \(250\leq{k}\leq{349}\), not sufficient, as hundreds digit of k can be 2 or 3.

(2) The tens digit of K + 25 is 7 --> \(x70\leq{k+25}\leq{x79}\) --> \(x45\leq{k}\leq{x54}\). Clearly insufficient to get \(x\).

(1)+(2) Hundreds digit still can be 2 (for example if k=250) or 3 (for example if k=345). Not sufficient.

Basically we have that: \(250\leq{k}\leq{254}\) or \(345\leq{k}\leq{349}\).

Answer: E.
_________________

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

General Discussion
Intern
Intern
avatar
Joined: 18 Mar 2010
Posts: 32
Re: if k is a 3 digit positive number  [#permalink]

Show Tags

New post 10 Nov 2010, 01:09
Let us assume that the k="ABC" => K= 100 (A) +10 (B) + C

According to statement 1: The hundred digit of k+150 is 4
K+150= 100 (A) +10 (B) + C + 150
k+150= 100 (A) + 100 + 10 (B) + 50 + C
K+150= 100 (A+1) +10 (B+5) + C

A+1=4 => A=3

Statement 1 is sufficient.

According to statement 2: The tens digit of k+25 is 7

K+25= 100 (A) +10 (B) + C + 25
= 100 (A) + 10 (B+2) + (C+5)

B+2=7 => B=5

Statement 2 is insufficient because it tell us nothing about the hundreds place



Answer is A
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51229
Re: if k is a 3 digit positive number  [#permalink]

Show Tags

New post 10 Nov 2010, 01:15
1
rockroars wrote:
Let us assume that the k="ABC" => K= 100 (A) +10 (B) + C

According to statement 1: The hundred digit of k+150 is 4
K+150= 100 (A) +10 (B) + C + 150
k+150= 100 (A) + 100 + 10 (B) + 50 + C
K+150= 100 (A+1) +10 (B+5) + C

A+1=4 => A=3

Statement 1 is sufficient.

According to statement 2: The tens digit of k+25 is 7

K+25= 100 (A) +10 (B) + C + 25
= 100 (A) + 10 (B+2) + (C+5)

B+2=7 => B=5

Statement 2 is insufficient because it tell us nothing about the hundreds place



Answer is A


Red part is not correct. OA for this question is E, not A. Refer for the solution to my post above.
_________________

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

Intern
Intern
avatar
Joined: 18 Mar 2010
Posts: 32
Re: if k is a 3 digit positive number  [#permalink]

Show Tags

New post 10 Nov 2010, 01:28
Thank You for your response, I will go through the solution provided by you.

But I am interested to know why the red part highlighted by you is not correct?
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51229
Re: if k is a 3 digit positive number  [#permalink]

Show Tags

New post 10 Nov 2010, 01:51
1
rockroars wrote:
Thank You for your response, I will go through the solution provided by you.

But I am interested to know why the red part highlighted by you is not correct?


Note that when you represent 3-digit number as \(100A+10B+C\): A, B and C must be digits from 0 to 9 (for A from 1 to 9).

Now, when you get \(K+150=100(A+1)+10(B+5)+C\) you can not say that it's a representation of 3-digit number where A+1 is hundreds digit, B+5 tens digit and C units digit as we don't know whether B+5 is in the range from 0 to 9, because if it's more than 9 then you'll have A+1 plus 1 hundreds: A+1+1=4 --> A=2.

Hope it's clear.
_________________

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

Intern
Intern
avatar
Joined: 18 Mar 2010
Posts: 32
Re: if k is a 3 digit positive number  [#permalink]

Show Tags

New post 10 Nov 2010, 02:45
Perfect! Thank You :)
Director
Director
User avatar
G
Joined: 26 Oct 2016
Posts: 640
Location: United States
Concentration: Marketing, International Business
Schools: HBS '19
GMAT 1: 770 Q51 V44
GPA: 4
WE: Education (Education)
Re: If k is a 3 digit positive number, what is the hundred digit  [#permalink]

Show Tags

New post 12 Feb 2017, 17:28
In general, with problems like this one, just consider the EXTREMES of any possible range they throw at you.

If the hundreds digit of (k + 150) is 4, then take that to mean that
400 <= k + 150 <= 499
or
250 <= k <= 349.

Therefore, the hundreds digit of k can be either 2 or 3, so this statement is insufficient.

Note that you don't have to set up the inequalities to solve the problem: you can just notice that the biggest possible value for (k + 150) is 499, and that the smallest possible value for that expression is 400.

Hence E.
_________________

Thanks & Regards,
Anaira Mitch

Intern
Intern
avatar
B
Joined: 09 Apr 2018
Posts: 31
GPA: 4
Re: If k is a 3 digit positive number, what is the hundred digit  [#permalink]

Show Tags

New post 11 Sep 2018, 06:59
I thought about possible "carry overs", i.e. adding an imaginary digit when you do the written method for addition and a sum of digits is >10.

Ex. 18
+ 23

= 41

Here 8+3=11-> 11 is 1 bigger than 10, so you carry the 1 over to the next "column".

Using this approach let us assess the 2 statements:

(1) No info about hundreds digit, thus insufficient.

(2) Assuming no carry over from the tens to the hundreds digit, the hundreds digit could be 3.
However, assuming a carry over of 1 from the tens to the hundreds digit, the hundreds digit could also be 2. Since more than 1 value for the hundreds digtit is possible, statement (2) is insufficient.

(1) & (2) Using the same reasoning from above, combining the 2 statements does not provide any new information. The hundreds digit could still be 3 or 2.

Hence, the answer is E.

If you liked this post, feel free to hit Kudos!
GMAT Club Bot
Re: If k is a 3 digit positive number, what is the hundred digit &nbs [#permalink] 11 Sep 2018, 06:59
Display posts from previous: Sort by

If k is a 3 digit positive number, what is the hundred digit

  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®.