Welcome! Check out our free B-School Guides to learn how you compare with other applicants.
Login or Register
 

More Primes

This topic has 6 expert replies and 70 member replies
Goto page Previous Next
Bookmark
Previous Topic Next Topic

GMAT/MBA Expert

Stuart Kovinsky GMAT Instructor
Joined
08 Jan 2008
Posted:
3156 messages
Followed by:
461 members
Thanked:
1433 times
GMAT Score:
800
Post Tue Apr 12, 2011 11:11 am
prashkrish wrote:
Why is the following not a possible outcome?

B, G, P, R refer to number of balls.

(11 * R) * (1 * B) * (5 * G) * (x * P) = 88,000

If the following 2 outcomes could occur..
(11 * R) * (1 * B) * (5 * G) * (x * P) = (11 * 1) * (1 * 10) * (5 * 20) * (8 * 1)

OR

(11 * R) * (B * 1) * (5 * G) * (x * P) = (11 * 1) * (1 * 8) * (5 * 20) * (10 * 1)

Purple could be 8 or 10..

Please help me understand...
As noted in my post above, you multiply the value of each chip by the values of all of the other chips.

So, if you have 1 blue chip, the total value of the blues is:

1^1 = 1.

Similarly, if you have 10 blue chips, the total value of the blues is:

1^10 = 1

not

1*10 = 10

which is what you did in your calculation.

_________________
Stuart Kovinsky, B.A. LL.B.
Kaplan Test Prep & Admissions
Toronto Office
1-800-KAP-TEST
www.kaptest.com

Learn more about me

Free GMAT Practice Test under Proctored Conditions! - Find a practice test near you or live and online in Kaplan's Classroom Anywhere environment. Register today!
maihuna GMAT Titan Default Avatar
Joined
28 Dec 2008
Posted:
1578 messages
Followed by:
7 members
Thanked:
80 times
GMAT Score:
720
Post Tue Apr 12, 2011 11:11 am
Ok got it, thanks Stuart as always. I think, though, the wordings are too weird.

Stuart Kovinsky wrote:
maihuna wrote:
Stuart : I am more confused about the following constraints: have you thought of that. Is the worth of purple chips more than green and less than the red ones:

How many Purple : 2 with 8 each = 8*2 = 16
Green : 3 with 5 each = 3*5 = 15
Red : 1 with 11 = 1*11 = 11

so 11<15<16 or R<G<P

What am I missing here?

mmukher wrote:
The purple chips are worth more than the green chips, but less than the red chips. A certain number of chips are then selected from the bag.
You're misinterpreting the statement to read "the sum of the purple chips is greater than that of the green chips, but less than that of the red chips"; it's not the sums that are being compared, but the values of the individual chips.

As we can see from the question:

Quote:
In a certain game, a large bag is filled with blue, green, purple and red chips worth 1, 5, x and 11 points each, respectively.
"respectively" means that you take them in the order given; in other words, blue chips are worth 1 each, green chips are worth 5 each, purple chips are worth x each and red chips are worth 11 each.

_________________
Charged up again to beat the beast Smile

eubschoolasp Just gettin' started! Default Avatar
Joined
04 Jun 2011
Posted:
15 messages
Post Sat Jun 11, 2011 10:37 am
Hi Stuart
I'm sorry but when it says "The purple chips are worth more than the green chips, but less than the red chips", for me it implies the 'worth' of the purple chips is being considered, and that would be the point for purple chips multiplied by the number of purple chips. I would agree with people that the language used indeed is ambiguous. To avoid any possible ambiguity, it should have clearly mentioned that the point value is lesser/ greater. Isn't it?

Ahmed MS Rising GMAT Star Default Avatar
Joined
06 Apr 2011
Posted:
74 messages
Post Wed Jun 15, 2011 6:11 am
First break down the value 88,000.

For example 88,000 / 5 =17,600

17,600 / 5 = 3,520

3,520 / 5 = 704

704/ 8 = 88

88 / 8 =11


Blue chips worth 1, so we can ignore it. Let take all the multiple values of 88,000.

So, it would be 5 * 5* 5* 8* 8* 11 = 88,000

As Blue = 1, Green =5, Red = 11 are given so obviously Purple = 8 (indeed)

Therefore we need 2 purple chips. Answer is “B”


I think we should come with easier and faster way to solve the problem as we will have very limited time in the real GMAT Exam.

Cheers!

Michelleleigha Just gettin' started! Default Avatar
Joined
30 Jun 2011
Posted:
2 messages
Post Wed Jul 06, 2011 6:45 am
there are 2 8's so the answer is B

88* 1000= 88,000
11*8= 88
5*5*5*8= 1000

I like to use the factor trees for quick results.

akhilsuhag Really wants to Beat The GMAT!
Joined
04 Jul 2011
Posted:
261 messages
Followed by:
3 members
Thanked:
45 times
Target GMAT Score:
720+
Post Sun Jul 10, 2011 1:37 am
this is how I did it:

88,000 = 11*5*5*5*64

Now 64 will be a multiple of x ans x is between 5 & 11 (6,7,8,9,10).

This leaves x= 8.

now, 8*8 = 64..
Therefore 2 8's.

So, x= 8 and we have 2 x's.

saurabh2525_gupta Rising GMAT Star Default Avatar
Joined
27 Oct 2010
Posted:
72 messages
Followed by:
1 members
Thanked:
2 times
Post Tue Jul 12, 2011 9:44 pm
The worth of purple chips has to be 8 because of above explained reasons. But the answer can A as well as B. This is how:-

We need a total product of 88000.
RED PURPLE GREEN BLUE
1*11 * 1*8 * 5*200 1*1 answer in this case is A
1*11 * 2*8 * 5*100 1*1 answer in this case is B

There is no restriction on the number of chips that have to be picked.

madhavsingh Just gettin' started! Default Avatar
Joined
10 Jul 2011
Posted:
1 messages
Post Fri Jul 15, 2011 11:45 pm
value of purple chip is 8.
number of purple chips can be either one of these nos: 1, 2, 4,5,8,10 ( and many others, including 1000).
The maximum no of purple chips is 1000.

saketk GMAT Destroyer! Default Avatar
Joined
19 Jun 2011
Posted:
608 messages
Followed by:
7 members
Thanked:
35 times
Target GMAT Score:
700+
Post Wed Aug 17, 2011 11:37 am
Blue- 1 -- total 1 or many doesn't matter as it's value is 1.
Green - 5 -- total 3
Purple - X --- total 2
Red - 11-- total 1
Note: I did this orally, so the total written against each was calculated after the prime factorization of 88000.

Given...

11>X>5

88000 =

2*5*2*5*2*5*11*2*2*2
8*8*5*5*5*11*1

To fit the condition, C can only be 8. Therefore, total 2.. Answer choice B

Deependra1 Rising GMAT Star
Joined
10 Apr 2011
Posted:
53 messages
Thanked:
1 times
Post Fri Aug 26, 2011 11:15 am
Answer should be C

hopefully

jsnipes Just gettin' started!
Joined
08 Mar 2011
Posted:
27 messages
Post Mon Sep 12, 2011 8:07 am
i need to get better at 'interpreting' these questions.

i just looked at and realized that 1x5x11=55. so in order to get to an even number such as 88k it would have to be multiplied by an even number. both 2 and 4 work in the answer column but i didn't know how to get to that last step and just guessed (the right guess, but irrelevant). thanks for the fine explanation stuart.

shourav rahman Just gettin' started!
Joined
20 May 2011
Posted:
3 messages
Post Mon Sep 12, 2011 9:11 am
each and every gmat verbal and quant questions of beat the gmat really imporves my basic. thnx beat the gmat and all of the participants.

smitalli Just gettin' started! Default Avatar
Joined
21 Sep 2011
Posted:
1 messages
Post Tue Sep 27, 2011 8:56 am
I get confused in what the question is asking. I understand how you got the answer but from the beginning I didn't know what the question was looking for. What does it mean by "the product of the point values", is it just the obvious. All the values multiplied by themselves equals 88,000?

way2ashish Rising GMAT Star
Joined
26 Sep 2011
Posted:
31 messages
Post Fri Sep 30, 2011 6:18 pm
Hi,
I dint get the last step

To get 2^6, we need two 8s: choose (b). ???
could u please elaborate on this

Stuart Kovinsky wrote:
mmukher wrote:
In a certain game, a large bag is filled with blue, green, purple and red chips worth 1, 5, x and 11 points each, respectively. The purple chips are worth more than the green chips, but less than the red chips. A certain number of chips are then selected from the bag. If the product of the point values of the selected chips is 88,000, how many purple chips were selected?

Options :
1
2
3
4
5


OA later.
We know that the purple chips are worth 6, 7, 8, 9 or 10 points each.

The blue chips are worth 1 point each, so we can ignore those.

Let's break 88000 down to primes:

88 * 1000

11 * 8 * 10 * 10 * 10

11 * 2 * 2 * 2 * 2 * 5 * 2 * 5 * 2 * 5

so:

2^6 * 5^3 * 11

Well, we're not getting any 2s out of the 1, 5 or 11, so all the 2s have to come from x.

Therefore, x has to be 6, 8 or 10.

x can't be 6, because we don't want any 3s.

If x were 10, it would give us 2s and 5s. So to get 6 2s we'd also have to take 6 5s, which is way more than we want.

Therefore, x MUST be 8.

To get 2^6, we need two 8s: choose (b).

Rastis Rising GMAT Star Default Avatar
Joined
21 Sep 2011
Posted:
88 messages
Followed by:
1 members
Thanked:
2 times
Test Date:
April 2012
Target GMAT Score:
700
Post Mon Oct 03, 2011 11:12 am
Is there an explanation to this problem that's written in English and easier to understand?

Goto page Previous Next

Best Conversation Starters
1 varun289 31 topics
2 sana.noor 23 topics
3 killerdrummer 21 topics
4 Rudy414 19 topics
5 sanaa.rizwan 14 topics
See More Top Beat The GMAT Members...

Most Active Experts
1 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

 199 posts
2 image description GMATGuruNY

The Princeton Review Teacher

 134 posts
3 image description Jim@StratusPrep

Stratus Prep

 106 posts
4 image description Anju@Gurome

Gurome

 47 posts
5 image description Jon@Admissionado

Admissionado

 39 posts
See More Top Beat The GMAT Experts