NEW HERE? LEARN MORE
closeclose
Last visit was: 03 May 2024, 09:26 It is currently 03 May 2024, 09:26
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

8.999999/3.001 - 3.999975/1.995 =

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 93025
Own Kudos [?]: 620943 [15]
Given Kudos: 81742
Send PM
CAT Tests Forum Quiz Mode
8.999999/3.001 - 3.999975/1.995 = [#permalink] New post   10 Feb 2023, 15:19
1
Kudos
14
Bookmarks
Expert Reply
00:00
A
B
C
D
E

Difficulty:

85% (hard)

Question Stats:

49% (02:20) correct 51% (01:45) wrong based on 114 sessions
Hide Show timer Statistics
\(\frac{8.999999}{3.001} - \frac{3.999975}{1.995} =\)

A. 0.994
B. 0.996
C. 0.998
D. 1
E. 1.002
ShowHide Answer
Official Answer
A
Most Helpful Reply
User avatar
L
gmatophobia
Quant Chat Moderator
Joined: 22 Dec 2016
Posts: 3110
Own Kudos [?]: 4213 [5]
Given Kudos: 1851
Location: India
Concentration: Strategy, Leadership
Send PM
CAT Tests Forum Quiz Mode
8.999999/3.001 - 3.999975/1.995 = [#permalink] New post   11 Feb 2023, 23:52
2
Kudos
3
Bookmarks
Bunuel wrote:
\(\frac{8.999999}{3.001} - \frac{3.999975}{1.995} =\)

A. 0.994
B. 0.996
C. 0.998
D. 1
E. 1.002


\(\frac{8.999999}{3.001} - \frac{3.999975}{1.995} =\)

\(\frac{9 - 10^{-6}}{3 + 10^{-3}} - \frac{4 - (25 * 10^{-6})}{2 - (5 * 10^{-3})} =\)

\(\frac{(3 - 10^{-3}) (3 + 10^{-3})}{(3 + 10^{-3})} - \frac{(2 + 5*10^{-3})( 2 - 5*10^{-3})}{2 - (5 * 10^{-3})} =\)

\((3 - 10^{-3}) - (2 + 5*10^{-3}) \)

\(3 - 10^{-3} - 2 - 5*10^{-3} \)

\(1 + 10^{-3} (-5 - 1) \)

\(1 - 10^{-3} (6) \)

\(1 - 0.006 \)

\(0.994\)

Option A
General Discussion
User avatar
B
deemat
Intern
Intern
Joined: 19 Sep 2021
Posts: 6
Own Kudos [?]: 1 [1]
Given Kudos: 69
Location: United States
Schools: Columbia CBS '24 Darden '24 Haas '24 McDonough '24 Kellogg '24 Wharton '24
Send PM
Re: 8.999999/3.001 - 3.999975/1.995 = [#permalink] New post   15 Feb 2023, 19:38
1
Kudos
gmatophobia wrote:
Bunuel wrote:
\(\frac{8.999999}{3.001} - \frac{3.999975}{1.995} =\)

A. 0.994
B. 0.996
C. 0.998
D. 1
E. 1.002


\(\frac{8.999999}{3.001} - \frac{3.999975}{1.995} =\)

\(\frac{9 - 10^{-6}}{3 + 10^{-3}} - \frac{4 - (25 * 10^{-6})}{2 - (5 * 10^{-3})} =\)

\(\frac{(3 - 10^{-3}) (3 + 10^{-3})}{(3 + 10^{-3})} - \frac{(2 + 5*10^{-3})( 2 - 5*10^{-3})}{2 - (5 * 10^{-3})} =\)

\((3 - 10^{-3}) - (2 + 5*10^{-3}) \)

\(3 - 10^{-3} - 2 - 5*10^{-3} \)

\(1 + 10^{-3} (-5 - 1) \)

\(1 - 10^{-3} (6) \)

\(1 - 0.006 \)

\(0.994\)

Option A



Could you stop here and just estimate?

\(\frac{9 - 10^{-6}}{3 + 10^{-3}} - \frac{4 - (25 * 10^{-6})}{2 - (5 * 10^{-3})} =\)

Like you know that 9/3 = 3.

Different signs in the second term means you're subtracting the result of the scientific notation, which is effectively 1 thousandth of 1, or very close to 3 ~2.999

Then for the other one, 4/2 = 2. And they're the same sign in the second term so you're adding. But you know that 25/5 means you are adding 5 thousandths or ~2.005.

Therefore, subtracting leaves .994 A
User avatar
G
Regor60
Senior Manager
Senior Manager
Joined: 21 Nov 2021
Posts: 435
Own Kudos [?]: 213 [0]
Given Kudos: 345
Send PM
Re: 8.999999/3.001 - 3.999975/1.995 = [#permalink] New post   16 Feb 2023, 09:12
deemat wrote:
gmatophobia wrote:
Bunuel wrote:
\(\frac{8.999999}{3.001} - \frac{3.999975}{1.995} =\)

A. 0.994
B. 0.996
C. 0.998
D. 1
E. 1.002


\(\frac{8.999999}{3.001} - \frac{3.999975}{1.995} =\)

\(\frac{9 - 10^{-6}}{3 + 10^{-3}} - \frac{4 - (25 * 10^{-6})}{2 - (5 * 10^{-3})} =\)

\(\frac{(3 - 10^{-3}) (3 + 10^{-3})}{(3 + 10^{-3})} - \frac{(2 + 5*10^{-3})( 2 - 5*10^{-3})}{2 - (5 * 10^{-3})} =\)

\((3 - 10^{-3}) - (2 + 5*10^{-3}) \)

\(3 - 10^{-3} - 2 - 5*10^{-3} \)

\(1 + 10^{-3} (-5 - 1) \)

\(1 - 10^{-3} (6) \)

\(1 - 0.006 \)

\(0.994\)

Option A



Could you stop here and just estimate?

\(\frac{9 - 10^{-6}}{3 + 10^{-3}} - \frac{4 - (25 * 10^{-6})}{2 - (5 * 10^{-3})} =\)

Like you know that 9/3 = 3.

Different signs in the second term means you're subtracting the result of the scientific notation, which is effectively 1 thousandth of 1, or very close to 3 ~2.999

Then for the other one, 4/2 = 2. And they're the same sign in the second term so you're adding. But you know that 25/5 means you are adding 5 thousandths or ~2.005.

Therefore, subtracting leaves .994 A


A test of how well this works would be trying it without knowing the answer;)

But, seriously, with answer choices this close together, you're being signaled that estimating is not a reliable substitute for an exact calculation

Posted from my mobile device
User avatar
B
gmathero911
Intern
Intern
Joined: 19 Mar 2023
Posts: 17
Own Kudos [?]: 22 [0]
Given Kudos: 0
Send PM
Re: 8.999999/3.001 - 3.999975/1.995 = [#permalink] New post   10 Apr 2024, 10:27
gmatophobia
How do you go from
3 - 10^-3 - 2 - 5 * 10^-3
to
1 + 10^-3 (-5 - 1)
GMAT Club Bot
gmatclubot
Re: 8.999999/3.001 - 3.999975/1.995 = [#permalink]
10 Apr 2024, 10:27
Moderators:
Bunuel
Math Expert
93024 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions