tough one

Expert replies

bblast: Legendary Member; Posts: 1077; Joined: Mon Dec 13, 2010 1:44 amFollowed by: 33 members; Thanked: 118 times; GMAT Score:710

by bblast » Thu Aug 11, 2011 7:21 am

A certain computer has 2000 megabytes of memory. Memory is considered "free" unless it is being used to run either the programs or the operating system, in which case it is called "in use." Are more than 500 megabytes "free"?

1>The total memory in use is 5 times the memory being used to run the operating system.
2>The amount of memory being used to run the programs is less than the amount of memory that is free.

C

Cheers !!

Quant 47-Striving for 50
Verbal 34-Striving for 40

My gmat journey :
https://www.beatthegmat.com/710-bblast-s ... 90735.html
My take on the GMAT RC :
https://www.beatthegmat.com/ways-to-bbla ... 90808.html
How to prepare before your MBA:
https://www.youtube.com/watch?v=upz46D7 ... TWBZF14TKW_

Like this post

Source: Beat The GMAT — Data Sufficiency | Thu Aug 11, 2011 7:21 am

gmatboost: Master | Next Rank: 500 Posts; Posts: 312; Joined: Tue Aug 02, 2011 3:16 pmFollowed by: 33 members; Location: New York City; Thanked: 130 times; GMAT Score:780

by gmatboost » Thu Aug 11, 2011 7:54 am

Free = F
Operating System = S
Programs = P

F + P + S = 2000
Is F > 500?

1. (P + S) = 5*S
P = 4S
F could be more or less than 500. Insufficient.

2. P < F
F could be more or less than 500. Insufficient.

Combined:
We can easily come up with an example when [spoiler]F > 500[/spoiler]. For example, [spoiler]F = 2000, P = 0, S = 0[/spoiler]. Or many other options.

The challenge is to see if we can come up with one where [spoiler]F <=500[/spoiler].
We should test this by trying [spoiler]F = 500[/spoiler]. The biggest P could be then is about 500 also. This leaves S to be 125. So, the total is not nearly 2000. F has to be bigger than 500.

Another way of reasoning is that since F > P = 4S, F is the biggest of the 3, so it must take up at least 1/3 of the 2000, which is bigger than 500.

Greg Michnikov, Founder of GMAT Boost

GMAT Boost offers 250+ challenging GMAT Math practice questions, each with a thorough video explanation, and 100+ GMAT Math video tips, each 90 seconds or less.
It's a total of 20+ hours of expert instruction for an introductory price of just $10.
View sample questions and tips without signing up, or sign up now for full access.

Also, check out the most useful GMAT Math blog on the internet here.

Like this post

bblast: Legendary Member; Posts: 1077; Joined: Mon Dec 13, 2010 1:44 amFollowed by: 33 members; Thanked: 118 times; GMAT Score:710

by bblast » Thu Aug 11, 2011 8:22 am

gmatboost wrote: Another way of reasoning is that since F > P = 4S, F is the biggest of the 3, so it must take up at least 1/3 of the 2000, which is bigger than 500.

awesome, Greg.

Like this post

GmatKiss: Legendary Member; Posts: 2789; Joined: Tue Jul 26, 2011 12:19 amFollowed by: 43 members; Location: Chennai, India; Thanked: 206 times; GMAT Score:640

by GmatKiss » Thu Aug 11, 2011 8:23 am

IMO:E

Like this post

GmatKiss: Legendary Member; Posts: 2789; Joined: Tue Jul 26, 2011 12:19 amFollowed by: 43 members; Location: Chennai, India; Thanked: 206 times; GMAT Score:640

by GmatKiss » Thu Aug 11, 2011 8:36 am

Hi GB,

Another way of reasoning is that since F > P = 4S, F is the biggest of the 3, so it must take up at least 1/3 of the 2000, which is bigger than 500

How can we reason so,
It is given in (2) that, P < F

Please help me out, if am wrong!

Last edited by GmatKiss on Thu Aug 11, 2011 8:48 am, edited 1 time in total.

Like this post

gmatboost: Master | Next Rank: 500 Posts; Posts: 312; Joined: Tue Aug 02, 2011 3:16 pmFollowed by: 33 members; Location: New York City; Thanked: 130 times; GMAT Score:780

by gmatboost » Thu Aug 11, 2011 8:37 am

F > P is the same as P < F
I just switched the order.

Like this post

GmatKiss: Legendary Member; Posts: 2789; Joined: Tue Jul 26, 2011 12:19 amFollowed by: 43 members; Location: Chennai, India; Thanked: 206 times; GMAT Score:640

by GmatKiss » Thu Aug 11, 2011 8:47 am

OMG!! thanks boost, for being so kind

Like this post

GMATGuruNY: GMAT Instructor; Posts: 15539; Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members; Location: New York, NY; Thanked: 13060 times; GMAT Score:790

by GMATGuruNY » Thu Aug 11, 2011 9:24 am

bblast wrote:A certain computer has 2000 megabytes of memory. Memory is considered "free" unless it is being used to run either the programs or the operating system, in which case it is called "in use." Are more than 500 megabytes "free"?

1>The total memory in use is 5 times the memory being used to run the operating system.
2>The amount of memory being used to run the programs is less than the amount of memory that is free.

C

Let F = free, P = programs, S = system.

Given that F+P+S = 2000, is F > 500?

Statement 1: P+S = 5S.
P = 4S
Thus, P > S.
No way to determine whether F > 500.

Statement 2: F > P.
No way to determine whether F > 500.

Statements 1 and 2 combined:
Since P > S and F > P:
F > P > S.
If F = 500, then P<500 and S<500, and F+P+S < 1500.
Thus, to satisfy the condition that F+P+S = 2000, F > 500.
Sufficient.

The correct answer is C.

Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

560 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review