It is currently 20 Oct 2017, 09:45

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Mark is playing poker at a casino. Mark starts playing with

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

Hide Tags

1 KUDOS received
VP
VP
avatar
Joined: 30 Sep 2004
Posts: 1480

Kudos [?]: 411 [1], given: 0

Location: Germany
Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 11 Nov 2004, 04:59
1
This post received
KUDOS
18
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

62% (03:58) correct 38% (03:30) wrong based on 286 sessions

HideShow timer Statistics

Mark is playing poker at a casino. Mark starts playing with 140 chips, 20% of which are $100 chips and 80% of which are $20 chips. For his first bet, Mark places chips, 10% of which are $100 chips, in the center of the table. If 70% of Mark's remaining chips are $20 chips, how much money did Mark bet?

A. $1,960
B. $1,740
C. $1,540
D. $3,080
E. $2,640
[Reveal] Spoiler: OA

Last edited by Bunuel on 17 Nov 2014, 12:26, edited 1 time in total.
Added the OA.

Kudos [?]: 411 [1], given: 0

4 KUDOS received
Senior Manager
Senior Manager
avatar
Joined: 19 May 2004
Posts: 291

Kudos [?]: 15 [4], given: 0

Re: Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 11 Nov 2004, 07:23
4
This post received
KUDOS
2
This post was
BOOKMARKED
A. 1960.

Let's say he bet X $100 chips, which means 9X $20 chips.
Out of the 140 chips, 112 are $20 chips and 28 are $100 chips.

0.7*(140-10X) = 112-9X.

You get X=7.

7*100 + 9*7*20 = 1960.

Kudos [?]: 15 [4], given: 0

Intern
Intern
avatar
Joined: 03 Aug 2009
Posts: 6

Kudos [?]: 1 [0], given: 0

Poker question [#permalink]

Show Tags

New post 24 Sep 2009, 00:14
1
This post was
BOOKMARKED
Can anyone let me know how you would approach a problem such as this one?

Mark is playing poker at a casino. Mark starts playing with
140 chips, 20% of which are $100 chips and 80% of which are
$20 chips. For his first bet, Mark places chips, 10% of
which are $100 chips, in the center of the table. If 70% of
Mark's remaining chips are $20 chips, how much money did
Mark bet?

A. $1,960
B. $1,740
C. $1,540
D. $3,080
E. $2,640

Thanks is advance.

Kudos [?]: 1 [0], given: 0

Intern
Intern
avatar
Joined: 23 Sep 2009
Posts: 12

Kudos [?]: [0], given: 0

Re: Poker question [#permalink]

Show Tags

New post 24 Sep 2009, 01:34
Total chips 140
20% of $100 chips = 28 chips * $100 = $2,800
80% of $20 chips = 112 chips * $20 = $2,240

If x is the number of chips bet and y is the amount of chips remaining:
x + y = 140
y = 140 - x ~ (1)

[First round bet] + [Second round bet] = $2,800 + $2,240
[0.1x * $100 + 0.9x * $20] + [0.3y * $100 + 0.7y * $20] = $5,040
10x + 18x + 30y + 14y = 5040
28x + 44y = 5040 ~ (2)

Substitute (1) into (2) to solve for x:
28x + 44(140 - x) = 5040
28x + 6160 - 44x = 5040
16x = 1120
x = 70

Substituting x:
[First round bet] = [0.1x * $100 + 0.9x * $20] = 0.1(70)($100)+0.9(70)($20) = $700 + $1,260 = $1,960

Answer is A

Kudos [?]: [0], given: 0

Manager
Manager
avatar
Joined: 27 Oct 2008
Posts: 185

Kudos [?]: 164 [0], given: 3

Re: Poker question [#permalink]

Show Tags

New post 24 Sep 2009, 11:41
Mark is playing poker at a casino. Mark starts playing with
140 chips, 20% of which are $100 chips and 80% of which are
$20 chips. For his first bet, Mark places chips, 10% of
which are $100 chips, in the center of the table. If 70% of
Mark's remaining chips are $20 chips, how much money did
Mark bet?

A. $1,960
B. $1,740
C. $1,540
D. $3,080
E. $2,640

Thanks is advance.

Soln:
Total is 140 chips
so 100$ chips is 28
and 20$ chips is 112

let he bet X chips.
of this .1X chips are 100$ chips and .9X chips are 20$ chips

the left over chips are (140-X)
of this .3(140-X) are 100$ chips and .7(140-X) are 20$ chips

thus equation is
.1X + .3(140-X) = 28
solving for X
X = 70
thus the betting involved 7 (100$) chips and 63 (20$) chips
amount is = 7 * 100 + 63 * 20 = 1960

Kudos [?]: 164 [0], given: 3

Manager
Manager
avatar
Joined: 10 Sep 2014
Posts: 99

Kudos [?]: 49 [0], given: 25

Re: Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 17 Nov 2014, 12:22
bump for a good practice question :)

If Mark has 140 chips and 20% are $100 chips, then Mark has 1/5 of 140 or 28 $100 chips. The other 112 are $20 chips.

10% of the chips he bet were $100 chips so for every 10 chips he bet, the total must have been $100 + 9($20) = $280. We can divide each answer choice by this # to see which one works.

A. 1960/280 = 7, meaning that Frank bet 7 $100 chips and 63 $20 chips. This would bring his total chip count to 140-7-63=70 chips and his $20 chip count down to 112-63=59 chips. So he has 59/70 $20 chips remaining. 70% is what we are looking for which is slighly less than 3/4 and this fraction is much more than that so we need a bigger answer.

B. we need a # larger than answer A so this wont work
C. same reason as above
D. 3080 / 280 = 11 meaning Frank bet 11 $100 chips and 99 $20 chips. He now has 30 chips left, 13 of which are $20 chips. 13/20 = 65/100 = 65% this is too small so we know Frank must have bet less money.

Answer E!

Kudos [?]: 49 [0], given: 25

Expert Post
6 KUDOS received
Veritas Prep GMAT Instructor
User avatar
G
Joined: 16 Oct 2010
Posts: 7676

Kudos [?]: 17369 [6], given: 232

Location: Pune, India
Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 17 Nov 2014, 23:47
6
This post received
KUDOS
Expert's post
6
This post was
BOOKMARKED
christoph wrote:
Mark is playing poker at a casino. Mark starts playing with 140 chips, 20% of which are $100 chips and 80% of which are $20 chips. For his first bet, Mark places chips, 10% of which are $100 chips, in the center of the table. If 70% of Mark's remaining chips are $20 chips, how much money did Mark bet?

A. $1,960
B. $1,740
C. $1,540
D. $3,080
E. $2,640


Initially, he had 80% $20 chips. Then he bet an amount in which he had 90% $20 chips and was left with an amount in which there were 70% $20 chips. Since 80% is the mid of 70% and 90%, it means the number of chips in the two cases were equal. So he bet a total of 140/2 = 70 chips.

7 must be $100 chips with value $700
63 must be $20 chips with value 63*20 = $1260
Total value of the bet = $1960

Answer (A)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Kudos [?]: 17369 [6], given: 232

Intern
Intern
User avatar
Joined: 25 Jun 2014
Posts: 46

Kudos [?]: 23 [0], given: 187

Re: Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 18 Nov 2014, 01:37
VeritasPrepKarishma wrote:
christoph wrote:
Mark is playing poker at a casino. Mark starts playing with 140 chips, 20% of which are $100 chips and 80% of which are $20 chips. For his first bet, Mark places chips, 10% of which are $100 chips, in the center of the table. If 70% of Mark's remaining chips are $20 chips, how much money did Mark bet?

A. $1,960
B. $1,740
C. $1,540
D. $3,080
E. $2,640


Initially, he had 80% $20 chips. Then he bet an amount in which he had 90% $20 chips and was left with an amount in which there were 70% $20 chips. Since 80% is the mid of 70% and 90%, it means the number of chips in the two cases were equal. So he bet a total of 140/2 = 70 chips.

7 must be $100 chips with value $700
63 must be $20 chips with value 63*20 = $1260
Total value of the bet = $1960

Answer (A)


Karishma, I love your weighted method but for this one, i was confused to figure out the reasoning behind it. So sorry but can you elaborate further? Thank you.

Kudos [?]: 23 [0], given: 187

Expert Post
Veritas Prep GMAT Instructor
User avatar
G
Joined: 16 Oct 2010
Posts: 7676

Kudos [?]: 17369 [0], given: 232

Location: Pune, India
Re: Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 18 Nov 2014, 20:48
Expert's post
1
This post was
BOOKMARKED
vietnammba wrote:
VeritasPrepKarishma wrote:
christoph wrote:
Mark is playing poker at a casino. Mark starts playing with 140 chips, 20% of which are $100 chips and 80% of which are $20 chips. For his first bet, Mark places chips, 10% of which are $100 chips, in the center of the table. If 70% of Mark's remaining chips are $20 chips, how much money did Mark bet?

A. $1,960
B. $1,740
C. $1,540
D. $3,080
E. $2,640


Initially, he had 80% $20 chips. Then he bet an amount in which he had 90% $20 chips and was left with an amount in which there were 70% $20 chips. Since 80% is the mid of 70% and 90%, it means the number of chips in the two cases were equal. So he bet a total of 140/2 = 70 chips.

7 must be $100 chips with value $700
63 must be $20 chips with value 63*20 = $1260
Total value of the bet = $1960

Answer (A)


Karishma, I love your weighted method but for this one, i was confused to figure out the reasoning behind it. So sorry but can you elaborate further? Thank you.


Look, that's the thing about weighted averages - don't think of them only after you see terms such as average, mixture etc. They are useful whenever you talk about two groups separately and then together or about one group splitting into two groups.

Here, he has a bunch of 140 chips first with a concentration of 80% $20 chips. He splits the bunch into two groups:
One he bets with a concentration of 90% $20 chips
The other he keeps with a concentration of 70% $20 chips

The mix is the initial bunch. The 70% group combined with 90% group gives the 80% initial bunch of chips.
Now using the usual formula, w1/w2 = (90 - 80)/(80 - 70) = 1:1

The two groups will have equal chips.

Does the use of weighted avgs make sense now?
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Kudos [?]: 17369 [0], given: 232

Intern
Intern
avatar
Joined: 25 Jan 2013
Posts: 35

Kudos [?]: 66 [0], given: 12

Location: Spain
Concentration: Finance, Other
Schools: Wharton '17 (S)
GMAT 1: 740 Q49 V42
Re: Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 19 Nov 2014, 04:57
Karishma,

Thanks for sharing your knowledge. Could you please do the same with the 100 $ chips?

Thanks in advance

Posted from my mobile device

Kudos [?]: 66 [0], given: 12

Intern
Intern
User avatar
Joined: 25 Jun 2014
Posts: 46

Kudos [?]: 23 [0], given: 187

Re: Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 19 Nov 2014, 09:15
Great explaination as usual Karishma, thank you so much :)

Kudos [?]: 23 [0], given: 187

Expert Post
1 KUDOS received
Veritas Prep GMAT Instructor
User avatar
G
Joined: 16 Oct 2010
Posts: 7676

Kudos [?]: 17369 [1], given: 232

Location: Pune, India
Re: Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 19 Nov 2014, 20:37
1
This post received
KUDOS
Expert's post
spla626 wrote:
Karishma,

Thanks for sharing your knowledge. Could you please do the same with the 100 $ chips?

Thanks in advance

Posted from my mobile device



Yes, you can do the same with the other "ingredient" as well.

The mix has 20% $100 chips, he bet a bunch that has 10% $100 chips and was left with the other bunch that has 30% $100 chips.
w1/w2 = (30 - 20)/(20 - 10) = 1:1

Both bunches are equal.
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Kudos [?]: 17369 [1], given: 232

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 16633

Kudos [?]: 273 [0], given: 0

Premium Member
Re: Poker question [#permalink]

Show Tags

New post 17 Jul 2015, 09:50
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 273 [0], given: 0

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 16633

Kudos [?]: 273 [0], given: 0

Premium Member
Re: Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 22 Jul 2016, 05:51
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 273 [0], given: 0

Manager
Manager
User avatar
Joined: 05 Jul 2016
Posts: 50

Kudos [?]: 10 [0], given: 129

Location: China
Concentration: Finance, Nonprofit
GMAT 1: 680 Q49 V33
GMAT 2: 690 Q51 V31
GMAT 3: 710 Q50 V36
GPA: 3.4
Mark is playing poker at a casino. Mark starts playing with [#permalink]

Show Tags

New post 31 Jul 2016, 20:34
I prefer creating a list to solve such before/after work problems:

$-----------original#--------- 1st bet#----------reminding#
100--------0.2n---------------0.1m--------------0.2n-0.1m
20---------0.8n----------------0.9m--------------0.8n-0.9m
total--------n-------------------m------------------n-m

we have known that (n-m)70%=0.8n-0.9m, and n=140
So m=70

Consequently, the money mark bet is 0.1*70*100+0.9*70*20=1960

Thanks,
_________________

It's better to burn out than to fade away.

Kudos [?]: 10 [0], given: 129

Mark is playing poker at a casino. Mark starts playing with   [#permalink] 31 Jul 2016, 20:34
Display posts from previous: Sort by

Mark is playing poker at a casino. Mark starts playing with

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


cron

GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.