It is currently 22 Feb 2018, 20:37

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# decimals

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Manager
Joined: 04 Sep 2006
Posts: 113

### Show Tags

31 May 2009, 05:14
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 1 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

T is a set of 30 decimals, sum of which is S. All the decimals are classified to two groups: if the tenth¡¯ digit is even, the decimal rounds to the immediate greater integer (For example, 2.2=>3); if the tenth' digit is odd, the digits to the right of the decimal point are abandoned (For example, 2.1=>2). The sum of these integers is E. If 1/3 of the decimals have a even tenth's digit, which of the following could not be the value of E-S?
I. -16
II. 6
III. 10
Manager
Joined: 08 Feb 2009
Posts: 144
Schools: Anderson

### Show Tags

31 May 2009, 06:25
III, 10 cannot be the value of E-S.

$$\frac{1}{3}$$ of the decimals, or 10 decimals, have even tenth digit $$\Rightarrow$$ their actual value has been increased. i.e. 3.6 = 4
$$\frac{2}{3}$$ of the decimals, or 20 decimals, have odd tenth digit $$\Rightarrow$$ their actual value has been decreased. i.e. 3.5 = 3

When E has a maximum value, Maximum Positive value of E-S will result.

Lets assume the even decimals end in 0.2, which is rounded to the next highest integer $$\Rightarrow$$ there is a gain of 0.8 in each integer m]\Rightarrow[/m] Gain = 0.8 x 10 = +8
Lets assume the odd decimals end in 0.1, which is rounded to the next lowest integer $$\Rightarrow$$ there is a loss of 0.1 in each integer m]\Rightarrow[/m] Loss = 0.1 x 20 = -2
Therefore, net Gain = 8-2 = 6 = E-S.

When E has a Lowest value, Lowest value of E-S will result.

Lets assume the even decimals end in 0.8, which is rounded to the next highest integer $$\Rightarrow$$ there is a gain of 0.2 in each integer m]\Rightarrow[/m] Gain = 0.2 x 10 = +2
Lets assume the odd decimals end in 0.9, which is rounded to the next lowest integer $$\Rightarrow$$ there is a loss of 0.9 in each integer m]\Rightarrow[/m] Loss = 0.9 x 20 = -18
Therefore, net Loss = -18+2 = -16 = E-S.

The value of E-S has to be between 6 & -16.
Thus 10 is ruled out.
Manager
Joined: 04 Sep 2006
Posts: 113

### Show Tags

31 May 2009, 07:00
except this

\frac{1}{3} of the decimals, or 10 decimals, have even tenth digit \Rightarrow their actual value has been increased. i.e. 3.6 = 4 ( how did u get ? )
\frac{2}{3} of the decimals, or 20 decimals, have odd tenth digit \Rightarrow their actual value has been decreased. i.e. 3.5 = 3
other part of the solution sounds nice .
Manager
Joined: 08 Feb 2009
Posts: 144
Schools: Anderson

### Show Tags

31 May 2009, 07:08
vcbabu wrote:
except this

\frac{1}{3} of the decimals, or 10 decimals, have even tenth digit \Rightarrow their actual value has been increased. i.e. 3.6 = 4 ( how did u get ? )
\frac{2}{3} of the decimals, or 20 decimals, have odd tenth digit \Rightarrow their actual value has been decreased. i.e. 3.5 = 3
other part of the solution sounds nice .

I made changes to the solution I posted. Please go through the changes.
Senior Manager
Joined: 16 Jan 2009
Posts: 355
Concentration: Technology, Marketing
GMAT 1: 700 Q50 V34
GPA: 3
WE: Sales (Telecommunications)

### Show Tags

31 May 2009, 14:45
goldeneagle94 wrote:
III, 10 cannot be the value of E-S.

$$\frac{1}{3}$$ of the decimals, or 10 decimals, have even tenth digit $$\Rightarrow$$ their actual value has been increased. i.e. 3.6 = 4
$$\frac{2}{3}$$ of the decimals, or 20 decimals, have odd tenth digit $$\Rightarrow$$ their actual value has been decreased. i.e. 3.5 = 3

When E has a maximum value, Maximum Positive value of E-S will result.

Lets assume the even decimals end in 0.2, which is rounded to the next highest integer $$\Rightarrow$$ there is a gain of 0.8 in each integer m]\Rightarrow[/m] Gain = 0.8 x 10 = +8
Lets assume the odd decimals end in 0.1, which is rounded to the next lowest integer $$\Rightarrow$$ there is a loss of 0.1 in each integer m]\Rightarrow[/m] Loss = 0.1 x 20 = -2
Therefore, net Gain = 8-2 = 6 = E-S.

When E has a Lowest value, Lowest value of E-S will result.

Lets assume the even decimals end in 0.8, which is rounded to the next highest integer $$\Rightarrow$$ there is a gain of 0.2 in each integer m]\Rightarrow[/m] Gain = 0.2 x 10 = +2
Lets assume the odd decimals end in 0.9, which is rounded to the next lowest integer $$\Rightarrow$$ there is a loss of 0.9 in each integer m]\Rightarrow[/m] Loss = 0.9 x 20 = -18
Therefore, net Loss = -18+2 = -16 = E-S.

The value of E-S has to be between 6 & -16.
Thus 10 is ruled out.

Nice expln goldeneagle94.
IMO '10'
_________________

Lahoosaher

Intern
Joined: 12 May 2009
Posts: 46
Location: Mumbai

### Show Tags

01 Jun 2009, 04:37
IMO 10

E-S =>
(i) (10 * 0.8) - (20 * 0.1) = 8-2 = 6
(ii) (10 * 0.2) - (20 * 0.9) = 2 - 18 = -16,

Out of the options 10 is left out and 10 cannot be the value of E-S

Thanks,
Senior Manager
Joined: 08 Jan 2009
Posts: 324

### Show Tags

01 Jun 2009, 21:34
Great explaination goldeneagle94
Re: decimals   [#permalink] 01 Jun 2009, 21:34
Display posts from previous: Sort by

# decimals

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.