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

It is currently 17 Aug 2018, 16:04

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

Three pounds of 05 grass seed contain 5 percent herbicide. A different

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

Hide Tags

Intern
Intern
avatar
Joined: 10 Dec 2012
Posts: 1
GMAT ToolKit User
Three pounds of 05 grass seed contain 5 percent herbicide. A different  [#permalink]

Show Tags

New post Updated on: 19 Oct 2014, 12:16
2
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

83% (01:23) correct 17% (03:44) wrong based on 132 sessions

HideShow timer Statistics

Three pounds of 05 grass seed contain 5 percent herbicide. A different type of grass seed, 20, which contains 20 percent herbicide, will be mixed with three pounds of 05 grass seed. How much grass seed of type 20 should be added to the three pounds of 05 grass seed so that the mixture contains 15 percent herbicide?

A. 3
B. 3.75
C. 4.5
D. 6
E. 9

Originally posted by zadi on 19 Oct 2014, 12:07.
Last edited by Bunuel on 19 Oct 2014, 12:16, edited 1 time in total.
Renamed the topic and edited the question.
Senior Manager
Senior Manager
User avatar
Joined: 13 Jun 2013
Posts: 277
Premium Member
Re: Three pounds of 05 grass seed contain 5 percent herbicide. A different  [#permalink]

Show Tags

New post 19 Oct 2014, 13:35
3
zadi wrote:
Three pounds of 05 grass seed contain 5 percent herbicide. A different type of grass seed, 20, which contains 20 percent herbicide, will be mixed with three pounds of 05 grass seed. How much grass seed of type 20 should be added to the three pounds of 05 grass seed so that the mixture contains 15 percent herbicide?

A. 3
B. 3.75
C. 4.5
D. 6
E. 9


05 grass seed contains 5% herbicide and its amount is 3 pound
20 grass seed contains 20% herbicide and its amount is x

when these two types of grass seeds are mixed, their average becomes 15%

thus we have
3(5)+x(20)/(x+3) = 15

15+20x=15x +45
5x=30
or x=6
Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8188
Location: Pune, India
Re: Three pounds of 05 grass seed contain 5 percent herbicide. A different  [#permalink]

Show Tags

New post 19 Oct 2014, 21:24
2
zadi wrote:
Three pounds of 05 grass seed contain 5 percent herbicide. A different type of grass seed, 20, which contains 20 percent herbicide, will be mixed with three pounds of 05 grass seed. How much grass seed of type 20 should be added to the three pounds of 05 grass seed so that the mixture contains 15 percent herbicide?

A. 3
B. 3.75
C. 4.5
D. 6
E. 9


Using weighted averages:

5% herbicide seed mixed with 20% herbicide seed to give 15% herbicide seed.

w1/w2 = (20 - 15)/(15 - 5) = 1/2

So 1 part of 5% was mixed with 2 parts of 20%.
Since 5% herbicide seed was 3 pounds, 20% herbicide seed must have been 6 pounds.

Answer (D)
_________________

Karishma
Veritas Prep GMAT Instructor

Save up to $1,000 on GMAT prep through 8/20! Learn more here >

GMAT self-study has never been more personalized or more fun. Try ORION Free!

SC Moderator
avatar
V
Joined: 22 May 2016
Posts: 1904
Premium Member CAT Tests
Three pounds of 05 grass seed contain 5 percent herbicide. A different  [#permalink]

Show Tags

New post 27 Oct 2017, 13:31
1
zadi wrote:
Three pounds of 05 grass seed contain 5 percent herbicide. A different type of grass seed, 20, which contains 20 percent herbicide, will be mixed with three pounds of 05 grass seed. How much grass seed of type 20 should be added to the three pounds of 05 grass seed so that the mixture contains 15 percent herbicide?

A. 3
B. 3.75
C. 4.5
D. 6
E. 9

Weighted average as well, a slightly different version.*

The formula below makes it easier for me to see two mixtures with different concentrations and/or volumes are added to create a third, resultant, mixture with its concentration and volume.

A = mixture with .05 herbicide
x = mixture with .20 herbicide

We have 3 pounds of A.

.05(3) + .20(x) = .15(3 + x)
5(3) + 20x = 15(3 + x)
15 + 20x = 45 + 15x
5x = 30
x = 6

Answer D
*\((Concen_A)(Vol_A) + (Con_B)(Vol_B) = (Con_{A+B})(Vol_{A+B})\)
_________________

In the depths of winter, I finally learned
that within me there lay an invincible summer.

-- Albert Camus, "Return to Tipasa"

Three pounds of 05 grass seed contain 5 percent herbicide. A different &nbs [#permalink] 27 Oct 2017, 13:31
Display posts from previous: Sort by

Three pounds of 05 grass seed contain 5 percent herbicide. A different

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

Events & Promotions

PREV
NEXT


cron

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®.