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

It is currently 17 Oct 2018, 07:02

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

Jeff plans to lose weight by reducing his daily calorie intake each we

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

Hide Tags

Manager
Manager
User avatar
Status: Kitchener
Joined: 03 Oct 2013
Posts: 89
Location: Canada
Concentration: Finance, Finance
GPA: 2.9
WE: Education (Education)
Premium Member
Jeff plans to lose weight by reducing his daily calorie intake each we  [#permalink]

Show Tags

New post 13 Mar 2015, 19:43
5
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

67% (00:51) correct 33% (01:10) wrong based on 180 sessions

HideShow timer Statistics

Jeff plans to lose weight by reducing his daily calorie intake each week. How many weeks does it take for his calorie intake to fall below half of its original level

(1) Jeff currently consumes 2,500 calories per day.
(2) Jeff plans to reduce his daily calorie intake by 10 percent each week.

_________________

Click +1 Kudos if my post helped

Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 6956
Re: Jeff plans to lose weight by reducing his daily calorie intake each we  [#permalink]

Show Tags

New post 13 Mar 2015, 20:11
23a2012 wrote:
Jeff plans to lose weight by reducing his daily calorie intake each week. How many weeks does it take for his calorie intake to fall below half of its original level

1.Jeff currently consumes 2,500 calories per day.
2.Jeff plans to reduce his daily calorie intake by 10 percent each week.


Hi,
Statement one just gives us intake , nothing about reduction. Insufficient
Statement two tells us the % reduction each week. Since the answer is also in terms of %, we donot require the value per se.
We can find when this reduction will lead to 50% reduction from 100%. Sufficient
Ans B
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

EMPOWERgmat Instructor
User avatar
V
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 12660
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: Jeff plans to lose weight by reducing his daily calorie intake each we  [#permalink]

Show Tags

New post 13 Mar 2015, 22:31
Hi 23a2012,

With certain DS questions, you have to pay careful attention to what is specifically ASKED for. The nature of the question might allow you more than one way to approach the work.

Here, we're asked how many weeks it will take Jeff to reduce his calorie intake by HALF.

Fact 1: Jeff currently consumes 2,500 calories per day.

This tells us nothing about how many calories he will reduce each week, so we cannot answer the question.
Fact 1 is INSUFFICIENT.

Fact 2: Jeff plans to reduce his daily calorie intake by 10 percent each week.

While we're not told Jeff's starting number of calories, THAT information is actually irrelevant here. We know that he's going to reduce his number of calories by 10% each week, so we COULD figure out how many weeks it takes to get that number down to HALF (meaning 50%). Here's how you could do the work, if you needed to...

By reducing the number by 10% each week, that is mathematically equivalent to multiplying the prior week's number by 0.9

Start = X
Week 1 = .9X
Week 2 = .9(.9X) = .81X
Week 3 = .9(.81X) = .729X
Week 4 = .9(.729X) = .6561X
Week 5 = .9(.6561X) = .59049X
Week 6 = .9(.59049X) = .531441X
Week 7 = .9(.531441X) = .4782969X

As you can see, the math IS rather tedious, but we don't actually have to do the math to answer this question. We know that we WOULD eventually get to the answer and THAT knowledge is enough.
Fact 2 is SUFFICIENT

Final Answer:

GMAT assassins aren't born, they're made,
Rich
_________________

760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save $75 + GMAT Club Tests Free
  Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

*****Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!*****

VP
VP
User avatar
V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1265
Location: India
Concentration: International Business, Operations
GMAT 1: 480 Q38 V22
GPA: 3.01
WE: Engineering (Consulting)
Premium Member Reviews Badge CAT Tests
Re: Jeff plans to lose weight by reducing his daily calorie intake each we  [#permalink]

Show Tags

New post 02 Jul 2018, 00:20
chetan2u wrote:
23a2012 wrote:
Jeff plans to lose weight by reducing his daily calorie intake each week. How many weeks does it take for his calorie intake to fall below half of its original level

1.Jeff currently consumes 2,500 calories per day.
2.Jeff plans to reduce his daily calorie intake by 10 percent each week.


Hi,
Statement one just gives us intake , nothing about reduction. Insufficient
Statement two tells us the % reduction each week. Since the answer is also in terms of %, we donot require the value per se.
We can find when this reduction will lead to 50% reduction from 100%. Sufficient
Ans B


What I did wrong with this question is that I thought we need initial calorie value which is to be reduced. Also, I referred both statements together when evaluated B.
_________________

"Do not watch clock; Do what it does. KEEP GOING."

Target Test Prep Representative
User avatar
P
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 3846
Location: United States (CA)
Re: Jeff plans to lose weight by reducing his daily calorie intake each we  [#permalink]

Show Tags

New post 04 Jul 2018, 19:05
23a2012 wrote:
Jeff plans to lose weight by reducing his daily calorie intake each week. How many weeks does it take for his calorie intake to fall below half of its original level

(1) Jeff currently consumes 2,500 calories per day.
(2) Jeff plans to reduce his daily calorie intake by 10 percent each week.


Statement One Alone:

Jeff currently consumes 2,500 calories per day.

Statement one is not sufficient to answer the question since we don’t know how much he plans to reduce his daily calorie intake.

Statement Two Alone:

Jeff plans to reduce his daily calorie intake by 10 percent each week.

Statement two is sufficient to answer the question. For example, if his daily calorie intake in the first week is 2000 calories, then his daily calorie intake in the second week is 2000 x 0.9 = 1800 calories. His daily calorie intake in the third week is 1800 x 0.9 = 1620 calories. Therefore, by continuing this process, we can find the number of weeks it takes for his calorie intake to fall below half its original level. (Note: We don’t have to find the actual number of weeks; we only need to know it’s possible to find it.)

Answer: B
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

GMAT Club Bot
Re: Jeff plans to lose weight by reducing his daily calorie intake each we &nbs [#permalink] 04 Jul 2018, 19:05
Display posts from previous: Sort by

Jeff plans to lose weight by reducing his daily calorie intake each we

  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®.