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

 It is currently 13 Oct 2019, 22:49

### 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

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

# How many pounds of fertilizer that is 10 percent nitrogen must be adde

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58335
How many pounds of fertilizer that is 10 percent nitrogen must be adde  [#permalink]

### Show Tags

31 Oct 2017, 00:05
00:00

Difficulty:

25% (medium)

Question Stats:

78% (01:46) correct 22% (02:11) wrong based on 207 sessions

### HideShow timer Statistics

How many pounds of fertilizer that is 10 percent nitrogen must be added to 12 pounds of fertilizer that is 20 percent nitrogen so that the resulting mixture is 18 percent nitrogen?

(A) 3
(B) 6
(C) 12
(D) 24
(E) 48

_________________
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8040
Location: United States (CA)
Re: How many pounds of fertilizer that is 10 percent nitrogen must be adde  [#permalink]

### Show Tags

01 Nov 2017, 17:05
3
2
Bunuel wrote:
How many pounds of fertilizer that is 10 percent nitrogen must be added to 12 pounds of fertilizer that is 20 percent nitrogen so that the resulting mixture is 18 percent nitrogen?

(A) 3
(B) 6
(C) 12
(D) 24
(E) 48

We add x pounds of fertilizer that is 10% nitrogen to 12 pounds of fertilizer that is 20% nitrogen, and the result is (x + 12) pounds of fertilizer that is 18% nitrogen. We can express this in the following equation:

0.1x + 0.2(12) = 0.18(x + 12)

10x + 20(12) = 18(x + 12)

10x + 240 = 18x + 216

24 = 8x

x = 3

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star 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.

##### General Discussion
Senior PS Moderator
Joined: 26 Feb 2016
Posts: 3337
Location: India
GPA: 3.12
Re: How many pounds of fertilizer that is 10 percent nitrogen must be adde  [#permalink]

### Show Tags

31 Oct 2017, 01:43
1
Bunuel wrote:
How many pounds of fertilizer that is 10 percent nitrogen must be added to 12 pounds of fertilizer that is 20 percent nitrogen so that the resulting mixture is 18 percent nitrogen?

(A) 3
(B) 6
(C) 12
(D) 24
(E) 48

10-------------20

--------18-------

2---------------8

Hence the ratios in which the mixtures are to be added are 1:4

Since we are adding 12 pounds of the 20 percent nitrogen mixture,
we will need 3 pounds of the 10 percent nitrogen mixture, so that
the resulting mixture has 18 percent nitrogen.

Therefore, we need 3 pounds of fertilizer mixture having 10 percent nitrogen(Option A)
_________________
You've got what it takes, but it will take everything you've got
Manager
Joined: 30 Nov 2016
Posts: 103
Location: India
Concentration: Finance, Strategy
How many pounds of fertilizer that is 10 percent nitrogen must be adde  [#permalink]

### Show Tags

31 Oct 2017, 04:16
2
20% nitrogen in 12 pounds of fertilizer is 12/5.
Let us consider the new amount of 10% nitrogen to be x. so the total amount of nitrogen content will be 12/5 + x/10. And the total amount of fertilizer will be 12+x.
$$\frac{(2.4+ 0.x)}{(12+x)}$$ =.18
X=3
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 9697
Location: Pune, India
Re: How many pounds of fertilizer that is 10 percent nitrogen must be adde  [#permalink]

### Show Tags

31 Oct 2017, 04:44
2
1
Bunuel wrote:
How many pounds of fertilizer that is 10 percent nitrogen must be added to 12 pounds of fertilizer that is 20 percent nitrogen so that the resulting mixture is 18 percent nitrogen?

(A) 3
(B) 6
(C) 12
(D) 24
(E) 48

Using weighted averages:

We need to mix 10% nitrogen fertiliser with 20% to get 18% nitrogen.

w1/w2 = (A2 - Aavg)/(Aavg - A1) = (20 - 18)/(18 - 10) = 1/4

For every 1 part of 10% nitrogen, we need 4 parts of 20% nitrogen.
Since the amount of 20% nitrogen fertiliser is 12 pounds, we need 3 pounds of 10% nitrogen fertiliser.

_________________
Karishma
Veritas Prep GMAT Instructor

Non-Human User
Joined: 09 Sep 2013
Posts: 13080
Re: How many pounds of fertilizer that is 10 percent nitrogen must be adde  [#permalink]

### Show Tags

02 Dec 2018, 05:41
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: How many pounds of fertilizer that is 10 percent nitrogen must be adde   [#permalink] 02 Dec 2018, 05:41
Display posts from previous: Sort by