Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 19 Apr 2010
Posts: 1

A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
Updated on: 13 Jun 2013, 02:18
Question Stats:
57% (01:59) correct 43% (02:25) wrong based on 653 sessions
HideShow timer Statistics
A certain shade of gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint. If 2 gallons of the mixture is needed and the individual colors can be purchased only in one gallon or half gallon cans, what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture? A. 2 B. 2 1/2 C. 3 D. 3 1/2 E. 4
Official Answer and Stats are available only to registered users. Register/ Login.
Originally posted by benmtchong on 29 May 2010, 13:11.
Last edited by Bunuel on 13 Jun 2013, 02:18, edited 2 times in total.
Added the OA




Math Expert
Joined: 02 Sep 2009
Posts: 59032

Re: Pease help
[#permalink]
Show Tags
29 May 2010, 13:34
overlord168 wrote: A certain shade of gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint. If 2 gallons of the mixture is needed and the individual colors can be purchased only in one gallon or half gallon cans, what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture?
a. 2 b. 2 1/2 c. 3 d 3 1/2 e. 4 2 gallon of gray paint needs \(2*\frac{3}{3+5}=2*\frac{3}{8}=\frac{3}{4}\) gallons of white paint and \(2*\frac{5}{8}=\frac{5}{4}\) gallons of black paint. To get \(\frac{3}{4}=0.75\) gallons of white paint we should purchase at least 1 gallon of white paint; To get \(\frac{5}{4}=1.25\) gallons of black paint we should purchase at least 1.5 gallons of black paint. Total: 1+1.5=2.5. Answer: B. Hope it helps.
_________________




Manager
Joined: 20 Apr 2010
Posts: 129
Location: I N D I A

Re: Pease help
[#permalink]
Show Tags
01 Jun 2010, 02:43
Doesn't 3 parts of white paint with 5 parts of black paint. play any role... plzz explain..im missing somewhere..
thanks



Math Expert
Joined: 02 Sep 2009
Posts: 59032

Re: Pease help
[#permalink]
Show Tags
01 Jun 2010, 04:10
sag wrote: Doesn't 3 parts of white paint with 5 parts of black paint. play any role... plzz explain..im missing somewhere..
thanks Gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint > total 8 parts > white 3/8 and black 5/8 > 2 gallon of gray paint needs \(2*\frac{3}{8}=\frac{3}{4}\) gallons of white paint and \(2*\frac{5}{8}=\frac{5}{4}\) gallons of black paint. Hope it's clear now.
_________________



Manager
Joined: 20 Apr 2010
Posts: 129
Location: I N D I A

Re: Pease help
[#permalink]
Show Tags
01 Jun 2010, 07:08
Thanks Bunuel.. Its crystal clear now.. now even ur 1st ans to this Q explains everything very clearly... Thanks once again... +1...



VP
Joined: 05 Mar 2008
Posts: 1346

Re: Mixture Problem
[#permalink]
Show Tags
22 Jul 2010, 08:49
TheSituation wrote: I've been banging my head against the wall on this one... someone please give me a simple straightforward solution and assurance that it was a very difficult question lol. A certain shade of gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint. If 2 gallons of the mixture is needed and the individual colors can be purchased only in onegallon or half gallon cans, what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture? (A) 2 (B) 2.5 (C) 3 (D) 3.5 (E) 4 OA: white = 3/8 black = 5/8 Combine both and that equals 1 gallon Multiply each by two to get 2 gallons (3/8)*2 + (5/8)*2 = 2 (3/8)*2 = 6/8 = 3/4 = .75 (5/8)*2 = 10/8 = 5/4 = 1.25 You need .75 gallons of white but since it comes in 1/2 or 1 you need 1 gallon You need 1.25 gallons of black but since it comes in 1/2 or 1 you need 1.5 1+1.5 = 2.5



Math Expert
Joined: 02 Sep 2009
Posts: 59032

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
13 Jun 2013, 03:09
Bumping for review and further discussion*. Get a kudos point for an alternative solution! *New project from GMAT Club!!! Check HERE
_________________



Intern
Joined: 29 May 2013
Posts: 5

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
30 Jun 2013, 09:25
Let one gallon be 80 liters. ( Assume smartly)
30 White +50 black = 80liters
According 2 question, we need 2 gallons i.e 160 liters. ( multiply above equation with 2)
60W+100B=160 ltrs
Minimum gallons for 60W=1 ( 1 gallon =80 liters, 1/2=40 liters) Minimum gallons for (80+20) B= 1+0.5=1.5 Total = 1+1.5=2.5
Ans. 2.5



Intern
Joined: 07 Oct 2012
Posts: 22
Location: India
Concentration: General Management, Finance
WE: Engineering (Other)

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
13 Jul 2013, 23:20
Given W:B = 3:5 That means say 3 gallons of white paint + 5 gallons of black paint = 8 gallons of paint mixture. But we want least amount of white & black paints for minimum of 2 gallons of mixture, so lets reduce keeping same ratio, 1.5 : 2.5 gives 1.5 + 2.5 = 4 gallons of mixture, but we want only 2 gallons, lets further reduce 0.75: 1.25 gives 1+1.5 = 2.5 gallons of mixture. This looks ok, but lets reduce further just to be sure 0.375: 0.625 gives 0.5 + 1 = 1.5 gallons of mixture, thats less than 2 gallons of mixture, so not acceptable. So correct ans is 2.5 gallons. B



Manager
Joined: 07 Dec 2009
Posts: 86
GMAT Date: 12032014

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
02 Aug 2014, 09:16
The mixture is made up of 3 parts white paint and 5 parts Black paint. Hence total is 8 parts make 2 gallons of mixture. 8x = 2(gallons) ==> x = 1/4
White paint needed = 3* 1/4 =0.75. Minimum White paint needed = 1 Black Paint needed = 5* 1/4 = 1.25 Minimum Black Paint needed = 1.5
Hence Answer = 2.5. B



Intern
Joined: 25 Mar 2014
Posts: 29

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
25 Nov 2014, 06:48
[...]in order to measure out the portions needed for the mixture?How can you measure 0,75 gallons if you have only buckets of 0,5 and 1 gallons? My answer: 2 cans of 1 gallon and 1 half can of black 1 can and a half of white result: 4 gallons! Unless you have an other bottle (or any thing to measure), you cannot separate 0,75 gallons! Bunuel



Math Expert
Joined: 02 Sep 2009
Posts: 59032

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
25 Nov 2014, 07:03
plaverbach wrote: [...]in order to measure out the portions needed for the mixture?How can you measure 0,75 gallons if you have only buckets of 0,5 and 1 gallons? My answer: 2 cans of 1 gallon and 1 half can of black 1 can and a half of white result: 4 gallons! Unless you have an other bottle (or any thing to measure), you cannot separate 0,75 gallons! Bunuel Please reread the solution. To get 2 gallons of gray paint we need \(\frac{3}{4}\) gallons of white paint and \(\frac{5}{4}\) gallons of black paint. To get \(\frac{3}{4}=0.75\) gallons of white paint we should purchase at least 1 gallon of white paint; To get \(\frac{5}{4}=1.25\) gallons of black paint we should purchase at least 1.5 gallons of black paint. Total: 1+1.5=2.5. Answer: B.
_________________



Senior Manager
Joined: 03 Apr 2013
Posts: 263
Location: India
Concentration: Marketing, Finance
GPA: 3

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
09 Nov 2016, 06:19
benmtchong wrote: A certain shade of gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint. If 2 gallons of the mixture is needed and the individual colors can be purchased only in one gallon or half gallon cans, what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture?
A. 2 B. 2 1/2 C. 3 D. 3 1/2 E. 4 I don't like the wording of the question! There is a possibility of two solutions here..all depends o what exactly "measure out" means to say in the question..and some information that I find is missing in the question. It should be clearly stated that one can measure out exactly as much as wanted from any can(example, one can take out 0.75 liters from a 1 liter can, and so forth). In this case, 2.5 is the correct answer. But if such thing is not possible, then we would have to work exclusively with 0.5 and 1 liter cans only, in which case, 4 will be the answer. I'm not sure if my argument is illfounded, but please, clarify. I request Bunuel to comment and also clarify, so I don't make such comprehension mistakes if I did so.
_________________
Spread some love..Like = +1 Kudos



Intern
Joined: 04 Jan 2017
Posts: 14

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
22 Feb 2017, 02:40
ShashankDave wrote: benmtchong wrote: A certain shade of gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint. If 2 gallons of the mixture is needed and the individual colors can be purchased only in one gallon or half gallon cans, what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture?
A. 2 B. 2 1/2 C. 3 D. 3 1/2 E. 4 I don't like the wording of the question! There is a possibility of two solutions here..all depends o what exactly "measure out" means to say in the question..and some information that I find is missing in the question. It should be clearly stated that one can measure out exactly as much as wanted from any can(example, one can take out 0.75 liters from a 1 liter can, and so forth). In this case, 2.5 is the correct answer. But if such thing is not possible, then we would have to work exclusively with 0.5 and 1 liter cans only, in which case, 4 will be the answer. I'm not sure if my argument is illfounded, but please, clarify. I request Bunuel to comment and also clarify, so I don't make such comprehension mistakes if I did so. I approached this question in the same way and made the same mistake. My assumption was that we would have to pour together the whole (1 or 1/2 gallon) cans so that we can get at least 2 liters of grey paint, which gives E as a result.



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 9777
Location: Pune, India

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
22 Feb 2017, 05:51
Scyzo wrote: ShashankDave wrote: benmtchong wrote: A certain shade of gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint. If 2 gallons of the mixture is needed and the individual colors can be purchased only in one gallon or half gallon cans, what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture?
A. 2 B. 2 1/2 C. 3 D. 3 1/2 E. 4 I don't like the wording of the question! There is a possibility of two solutions here..all depends o what exactly "measure out" means to say in the question..and some information that I find is missing in the question. It should be clearly stated that one can measure out exactly as much as wanted from any can(example, one can take out 0.75 liters from a 1 liter can, and so forth). In this case, 2.5 is the correct answer. But if such thing is not possible, then we would have to work exclusively with 0.5 and 1 liter cans only, in which case, 4 will be the answer. I'm not sure if my argument is illfounded, but please, clarify. I request Bunuel to comment and also clarify, so I don't make such comprehension mistakes if I did so. I approached this question in the same way and made the same mistake. My assumption was that we would have to pour together the whole (1 or 1/2 gallon) cans so that we can get at least 2 liters of grey paint, which gives E as a result. Look at the last line of the question: what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture? This clarifies that you need to find the least amount of paint that you need to buy to measure out the portions needed for 2 gallons mix. Otherwise, it would have been mentioned that you need to use the whole can.
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2812

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
20 Mar 2018, 16:50
benmtchong wrote: A certain shade of gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint. If 2 gallons of the mixture is needed and the individual colors can be purchased only in one gallon or half gallon cans, what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture?
A. 2 B. 2 1/2 C. 3 D. 3 1/2 E. 4 We are given that a gray pain is obtained by mixing 3 parts of white paint with 5 parts of black paint. We are also given that the paint can be purchased in one or halfgallon cans and that the total mixture is 2 gallons. We must determine the minimum number of gallons of paint of each color needed. Our given ratio is: w/b = 3/5 = 1.5/2.5 = 0.75/1.25 As we can see, we need to have 0.75 gallons of white paint and 1.25 gallons of black paint in order to have 2 gallons of the mixed (i.e., gray) paint. However, in order to have the 0.75 gallons of white paint, we need to purchase 1 gallon of white paint, and in order to have the 1.25 gallons of black paint, we need to purchase 1.5 gallons of black paint. Thus, we need to purchase a total of 2.5 gallons of paint. Answer: B
_________________
5star rated online GMAT quant self study course See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews
If you find one of my posts helpful, please take a moment to click on the "Kudos" button.



Intern
Joined: 03 Jul 2018
Posts: 36
Location: India
GMAT 1: 560 Q47 V28 GMAT 2: 560 Q47 V28 GMAT 3: 560 Q47 V28 GMAT 4: 560 Q47 V28
GPA: 3.88

Problem solvingneed help
[#permalink]
Show Tags
14 Jul 2018, 01:09
A certain shade of gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint. If 2 gallons of the mixture is needed and the individual colors can be purchased only in onegallon or half gallon cans, what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture? (A) 2 (B) 2&1/2 (C) 3 (D) 3&1/2 (E) 4



Math Expert
Joined: 02 Aug 2009
Posts: 8161

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
14 Jul 2018, 01:28
shard87 wrote: A certain shade of gray paint is obtained by mixing 3 parts of white paint with 5 parts of black paint. If 2 gallons of the mixture is needed and the individual colors can be purchased only in onegallon or half gallon cans, what is the least amount of paint, in gallons, that must be purchased in order to measure out the portions needed for the mixture? (A) 2 (B) 2&1/2 (C) 3 (D) 3&1/2 (E) 4 please search before posting. you are likely to get an answer every time. If you still have a problem, please revert.
_________________



NonHuman User
Joined: 09 Sep 2013
Posts: 13577

Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
Show Tags
29 Sep 2019, 21:44
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.
_________________




Re: A certain shade of gray paint is obtained by mixing 3 parts
[#permalink]
29 Sep 2019, 21:44






