The concentration of a certain chemical in a full water tank : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 28 Feb 2017, 06:45

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# The concentration of a certain chemical in a full water tank

Author Message
TAGS:

### Hide Tags

Manager
Joined: 06 May 2009
Posts: 76
Followers: 2

Kudos [?]: 96 [0], given: 3

The concentration of a certain chemical in a full water tank [#permalink]

### Show Tags

23 Jun 2009, 04:01
00:00

Difficulty:

25% (medium)

Question Stats:

78% (02:38) correct 22% (03:03) wrong based on 74 sessions

### HideShow timer Statistics

The concentration of a certain chemical in a full water tank depends on the depth of the water. At a depth that is x feet below the top of the tank, the concentration is $$3 + \frac{4}{\sqrt{5-x}}$$ parts per million, where 0 < x < 4. To the nearest 0.1 foot, at what depth is the concentration equal to 6 parts per million?

(A) 2.4 ft
(B) 2.5 ft
(C) 2.8 ft
(D) 3.0 ft
(E) 3.2 ft

OPEN DISCUSSION OF THIS QUESTION IS HERE: the-concentration-of-a-certain-chemical-in-a-full-water-tank-23165.html
[Reveal] Spoiler: OA
Senior Manager
Joined: 16 Jan 2009
Posts: 359
Concentration: Technology, Marketing
GMAT 1: 700 Q50 V34
GPA: 3
WE: Sales (Telecommunications)
Followers: 4

Kudos [?]: 201 [2] , given: 16

Re: concentration of certain chemical [#permalink]

### Show Tags

23 Jun 2009, 04:06
2
KUDOS
(3 + (4/sq root (5-x)))=6
(4/sq root (5-x))=3
sq root (5-x)=4/3
x=5-(16/9)
x=3.2
_________________

Lahoosaher

Manager
Joined: 06 May 2009
Posts: 76
Followers: 2

Kudos [?]: 96 [0], given: 3

Re: concentration of certain chemical [#permalink]

### Show Tags

23 Jun 2009, 06:18
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 14001
Followers: 592

Kudos [?]: 168 [0], given: 0

Re: concentration of certain chemical [#permalink]

### Show Tags

10 Apr 2014, 20:07
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.
_________________
Math Expert
Joined: 02 Sep 2009
Posts: 37154
Followers: 7276

Kudos [?]: 96857 [0], given: 10808

Re: The concentration of a certain chemical in a full water tank [#permalink]

### Show Tags

11 Apr 2014, 03:03
The concentration of a certain chemical in a full water tank depends on the depth of the water. At a depth that is x feet below the top of the tank, the concentration is $$3 + \frac{4}{\sqrt{5-x}}$$ parts per million, where 0 < x < 4. To the nearest 0.1 foot, at what depth is the concentration equal to 6 parts per million?

(A) 2.4 ft
(B) 2.5 ft
(C) 2.8 ft
(D) 3.0 ft
(E) 3.2 ft

Given: at a depth that is x feet below the top of the tank, the concentration is $$3 + \frac{4}{\sqrt{5-x}}$$ parts per million.

Question: at what depth, for which x, is the concentration equal to 6 parts per million? So, for which x, is $$3 + \frac{4}{\sqrt{5-x}}$$ equal to 6?

$$3 + \frac{4}{\sqrt{5-x}}=6$$ --> $$x\approx{3.2}$$.

OPEN DISCUSSION OF THIS QUESTION IS HERE: the-concentration-of-a-certain-chemical-in-a-full-water-tank-23165.html
_________________
Re: The concentration of a certain chemical in a full water tank   [#permalink] 11 Apr 2014, 03:03
Similar topics Replies Last post
Similar
Topics:
4 A fish tank is half full of water. If 10 gallons of water were added, 9 14 Jul 2015, 00:03
7 One filter decreases the concentration of harmful substances in water 4 25 Dec 2014, 12:52
46 The volume of water in a certain tank is x percent greater 20 20 Jan 2013, 00:49
11 One water pump can fill half of a certain empty tank in 3 hours. Anoth 9 04 Jan 2012, 09:17
If Henry were to add 5 gallons of water to a tank that is 2 05 Nov 2008, 15:26
Display posts from previous: Sort by