GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

It is currently 25 May 2020, 01:17

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

$x is enough for Bob to survive 45 days, while for Amy $x is enough to

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 64073
$x is enough for Bob to survive 45 days, while for Amy $x is enough to  [#permalink]

Show Tags

New post 27 Mar 2020, 03:53
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

79% (02:00) correct 21% (01:46) wrong based on 71 sessions

HideShow timer Statistics

GMATWhiz Representative
User avatar
G
Joined: 07 May 2019
Posts: 693
Location: India
Re: $x is enough for Bob to survive 45 days, while for Amy $x is enough to  [#permalink]

Show Tags

New post 27 Mar 2020, 05:32
Bunuel wrote:
$x is enough for Bob to survive 45 days, while for Amy $x is enough to survive only for 36 days. How many days they can survive together for total of $2x ?

A. 10 days
B. 20 days
C. 30 days
D. 40 days
E. 50 days

Solution


We can also solve it as time and work problem
    • Let’s assume x as the LCM(45, 36)
      o x = 180 units
    • The amount required by Bob to survive one day = \(\frac{180}{45} = 4\) units
    • The amount required by Amy to survive one day = \(\frac{180}{36} = 5\) units
      o The amount required by both of them together to survive one day = \(4 + 5 = 9\) units
      o In 180 units they can survive = \(\frac{180}{9} = 20\)days
      o With $ \(x\) they can survive = \(20\) days
      o With $\(2x\) they can survive =\(2*20=40\) days
Hence, the correct answer is Option D.

Alternative method:


    • The amount required by Bob to survive 45 days = x
      o The amount required by Bob to survive 1 day = \(\frac{x}{45}\)
    • The amount required by Amy to survive 36 days = x
      o The amount required by Amy to survive 1 day = \(\frac{x}{36}\)
    • Amount required by both of them to survive 1 day = \(\frac{x}{45} + \frac{x}{ 36} = \frac{(5x + 4x)}{180} = \frac{x}{20}\)
      o With \(\frac{x}{20}\) they both can survive 1 day
      o With \(x\), they can survive for 20days
      o With $ \(2x\) they can survive for 40 days
Thus, the correct answer is Option D.
_________________

GMAT Prep truly Personalized using Technology

Prepare from an application driven course that serves real-time improvement modules along with a well-defined adaptive study plan. Start a free trial to experience it yourself and get access to 25 videos and 300 GMAT styled questions.

Helpful Links

Score Improvement Strategy: How to score Q50+ on GMAT | 5 steps to Improve your Verbal score
Study Plan Articles: 3 mistakes to avoid while preparing | How to create a study plan? | The Right Order of Learning | Importance of Error Log
Helpful Quant Strategies: Filling Spaces Method | Avoid Double Counting in P&C | The Art of Not Assuming anything in DS | Number Line Method
Key Verbal Techniques: Plan-Goal Framework in CR | Quantifiers the tiny Game-changers | Countable vs Uncountable Nouns | Tackling Confusing Words in Main Point
Manager
Manager
avatar
B
Joined: 30 Jun 2019
Posts: 208
Re: $x is enough for Bob to survive 45 days, while for Amy $x is enough to  [#permalink]

Show Tags

New post 31 Mar 2020, 14:51
x = r1*45 -->r1=x/45
x = r2*36 --> r2=x/36

2x = (x/45+x/36)t
2x = (4x/180+5x/180)t
2x = (9x/180)t
2x = (x/20)t
40=t
Intern
Intern
avatar
Joined: 31 Mar 2020
Posts: 1
Re: $x is enough for Bob to survive 45 days, while for Amy $x is enough to  [#permalink]

Show Tags

New post 31 Mar 2020, 18:39
Bob =1/45,amy=1/36
Together 1/45+1/36=20days
$xdays=20days
$2xdays=2×20=40days

Posted from my mobile device
CrackVerbal Quant Expert
User avatar
P
Joined: 12 Apr 2019
Posts: 587
Re: $x is enough for Bob to survive 45 days, while for Amy $x is enough to  [#permalink]

Show Tags

New post 31 Mar 2020, 23:19
1
This is essentially a Time & Work question; do not let it fool you because it talks about money being spent. The money with which Bob/Amy can survive represents the work to be done.

As with most Time & Work problems, the LCM method works very well in this case. We can assume x to be the LCM of 45 and 36.
x = LCM (45,36) = $180

If Bob can survive 45 days with $180, it means he uses up $4 per day. Similarly, Amy uses up $5 per day. These values represent the individual rates of Bob and Amy.
If they have to survive together, they will consume a total of $9 per day. If a total of $360 is available, they can survive for a total of 40 days (\(\frac{360}{9}\)).

The correct answer option is D.

Hope that helps!
_________________
GMAT Club Bot
Re: $x is enough for Bob to survive 45 days, while for Amy $x is enough to   [#permalink] 31 Mar 2020, 23:19

$x is enough for Bob to survive 45 days, while for Amy $x is enough to

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





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