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

It is currently 21 Sep 2019, 00:06

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

If d represents the hundredths digit and e represents the

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

Hide Tags

Find Similar Topics 
Intern
Intern
User avatar
Joined: 15 Nov 2010
Posts: 4
If d represents the hundredths digit and e represents the  [#permalink]

Show Tags

New post Updated on: 03 Aug 2012, 00:01
2
16
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

50% (02:27) correct 50% (02:24) wrong based on 505 sessions

HideShow timer Statistics

If d represents the hundredths digit and e represents the thousandths digit in the decimal 0.4de, what is the value of this decimal rounded to the nearest tenth?

(1) d – e is equal to a positive perfect square.
(2) √d > e^2

Originally posted by ghostdude on 10 Jul 2011, 08:44.
Last edited by Bunuel on 03 Aug 2012, 00:01, edited 1 time in total.
OA added.
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58142
Re: If d represents the hundredths digit and e represents the  [#permalink]

Show Tags

New post 31 Jan 2012, 04:25
6
7
pbull78 wrote:
can anyone help me with detailed explanation ?


If d represents the hundredths digit and e represents the thousandths digit in the decimal 0.4de, what is the value of this decimal rounded to the nearest tenth?

To answer the question we should know whether \(d\geq{5}\).

(1) d – e is equal to a positive perfect square --> easy to get two different result: \(0.4de=0.451\) (5-1=4=2^2), then 0.4de rounded to the nearest tenth will be \(0.5\) but if \(0.4de=0.421\) (2-1=1=1^2), then 0.4de rounded to the nearest nearest tenth will be \(0.4\). Not sufficient.

(2) \(\sqrt{d}>e^2\) --> also easy to get two different result: if \(\sqrt{d}=\sqrt{5}>1^2=e^2\) or \(\sqrt{d}=\sqrt{2}>1^2=e^2\). Not sufficient.

(1)+(2) 0.451 and 0.421 satisfy both statements and give different values of 0.4de when rounded to the nearest tenth: 0.5 and 0.4. Not sufficient.

Answer: E.

Rounding rules
Rounding is simplifying a number to a certain place value. To round the decimal drop the extra decimal places, and if the first dropped digit is 5 or greater, round up the last digit that you keep. If the first dropped digit is 4 or smaller, round down (keep the same) the last digit that you keep.

Example:
5.3485 rounded to the nearest tenth = 5.3, since the dropped 4 is less than 5.
5.3485 rounded to the nearest hundredth = 5.35, since the dropped 8 is greater than 5.
5.3485 rounded to the nearest thousandth = 5.349, since the dropped 5 is equal to 5.

Hope it helps.
_________________
General Discussion
Retired Moderator
avatar
Joined: 20 Dec 2010
Posts: 1654
Re: Decimal Rounding DS  [#permalink]

Show Tags

New post 10 Jul 2011, 09:16
1
ghostdude wrote:
If d represents the hundredths digit and e represents the thousandths digit in the decimal 0.4de, what is the value of this decimal rounded to the nearest tenth?

(1) d – e is equal to a positive perfect square.
(2) √d > e^2


E
0.451. Decimal rounded tenth=0.5
0.421. Decimal rounded tenth=0.4
_________________
Intern
Intern
avatar
Joined: 16 Dec 2011
Posts: 38
GMAT Date: 04-23-2012
Re: If d represents the hundredths digit and e represents the  [#permalink]

Show Tags

New post 31 Jan 2012, 03:53
can anyone help me with detailed explanation ?
Senior Manager
Senior Manager
User avatar
Joined: 23 Oct 2010
Posts: 331
Location: Azerbaijan
Concentration: Finance
Schools: HEC '15 (A)
GMAT 1: 690 Q47 V38
GMAT ToolKit User
Re: If d represents the hundredths digit and e represents the  [#permalink]

Show Tags

New post 02 Aug 2012, 23:51
1
1
0.4de . question -0.x?

st1-d-e =perfect square.
let d-e=4 (d=4; e=0) or d-e=9 (d=9 e =0) insuff

st2- sqrootd>e^2
sqroot4>0 or sqroot9>0. again insuff. as everyone can understand, together these stmnts are also insuff
_________________
Happy are those who dream dreams and are ready to pay the price to make them come true

I am still on all gmat forums. msg me if you want to ask me smth
Manager
Manager
User avatar
Joined: 04 Oct 2013
Posts: 161
Concentration: Finance, Leadership
GMAT 1: 590 Q40 V30
GMAT 2: 730 Q49 V40
WE: Project Management (Entertainment and Sports)
Re: If d represents the hundredths digit and e represents the  [#permalink]

Show Tags

New post 14 Oct 2014, 02:43
ghostdude wrote:
If d represents the hundredths digit and e represents the thousandths digit in the decimal 0.4de, what is the value of this decimal rounded to the nearest tenth?

(1) d – e is equal to a positive perfect square.
(2) √d > e^2


we are allowed to use numbers < 10.

1. there are only 3 perfect squares in the available range. 1; 4; 9.

Pick 4. If d-e=4 then d might be 4 and e 0 or d might be 7 and e 3. If d=4 then our decimal remains 0.4; If d=7 our decimal becomes 0.5

NS.

2. since we know for sure that we are dealing with positive integers+0 we can safely say that if the square root of a number is greater than another number to the power of n, then the number under square root must be greater than the number to the power of n. This conveys us that d>e.

NS

1+2) Both cases on statement 1) hold. (E)
_________________
learn the rules of the game, then play better than anyone else.
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2594
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User
Re: If d represents the hundredths digit and e represents the  [#permalink]

Show Tags

New post 19 Nov 2016, 02:04
ghostdude wrote:
If d represents the hundredths digit and e represents the thousandths digit in the decimal 0.4de, what is the value of this decimal rounded to the nearest tenth?

(1) d – e is equal to a positive perfect square.
(2) √d > e^2


Amazing Question
Let n=0.4de
Here when we round n to nearest thousandths we will get either=>
0.4 for d≤4
OR
0.5 for d≥5
hence in this question we are concerned about the value of d.
statement 1
d-e=positive perfect square
numerous values are possible
e.g=>
n=0.454
n=0.487
n=0.421
n=9.451
Hence insufficient as we can have d<5 so ≥5.
Statement 2
hmm since d and e are both positive and we can square on both sides of any inequality for which both of its sides are positive
we get=> d>e^4
hmm numerous values are possible
e.g=>
n=0.421
n=0.491
n=0.451
etc
hence insufficient
combining the two statements we can still get two-bound cases
n=0.421
n=0.451
hence E
_________________
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 12428
Re: If d represents the hundredths digit and e represents the  [#permalink]

Show Tags

New post 09 Feb 2019, 03:10
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 Club Bot
Re: If d represents the hundredths digit and e represents the   [#permalink] 09 Feb 2019, 03:10
Display posts from previous: Sort by

If d represents the hundredths digit and e represents the

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





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