M24 #4 : GMAT Club Tests

M24 #4

Oldest

Best Reply

Author

Message

Intern

Joined: 18 Jan 2012

Posts: 46

Location: United States

Followers: 1

Kudos [?]: 36 [0], given: 21

Re: M24 #4 [#permalink]

03 Jul 2012, 00:19

Dce25 wrote:

Let the amount of acid in 80 gram solution(acid+water) be m grams:
So concentration= [m][/80]

water added = x gram
So new conc. = [m][/80+x]

Now Acc. to question [m][/80+x] = [1][/y] of [m][/80]

Solving we get: 80y = 80+x

Therefore each statement is sufficient.

Answer should be (D)

I believe that you have made incorrect inferences. The question stem ask about figuring out the original concentration of the acid. In other words, you have to figure out m.
_________________

-----------------------------------------------------------------------------------------------------
IT TAKES QUITE A BIT OF TIME AND TO POST DETAILED RESPONSES.
YOUR KUDOS IS VERY MUCH APPRECIATED
-----------------------------------------------------------------------------------------------------

Intern

Joined: 18 Jan 2012

Posts: 46

Location: United States

Followers: 1

Kudos [?]: 36 [0], given: 21

Re: M24 #4 [#permalink]

03 Jul 2012, 00:24

Dce25 wrote:

In Data sufficiency questions, its is exceptionally important to remain focused on what is being asked. AS per the question stem, What was the concentration of acid in the original solution?.
In other words, as per the variables that you have used, one is asked to figure out m/80.
Knowledge of "x" and "y" doesn't help us in achieving this objective
_________________

Manager

Joined: 14 Jun 2012

Posts: 66

Followers: 0

Kudos [?]: 6 [0], given: 1

Re: M24 #4 [#permalink]

31 Aug 2012, 20:23

Took the approach of setting up equations and then substituting the given values. Either statement individually is not sufficient since there are 2 variables X and Y.

Considering both the statements together, we get

Total weight of the new solution = 80+X = 80+80 =160

New concentration of acid = (1/Y) = 1/2

Since initial concentration of neither the water nor the acid is given we will be unable to solve the equations. Eg. if initial concentration of acid was say 40 gms then new concentration will be 20 whereas if initial conc of acid was 60 then new would be 30.

Thus I chose the statement E as the answer. Took me a minute and a half though. Will work on improving my speed.
_________________

My attempt to capture my B-School Journey in a Blog : tranquilnomadgmat.blogspot.com

There are no shortcuts to any place worth going.

Re: M24 #4 [#permalink] 31 Aug 2012, 20:23

		Similar topics	Author	Replies	Last post
Similar Topics:		m24 - 19	chengliu	2	24 May 2008, 18:59
	6	M24#34	ventivish	15	29 Nov 2008, 00:19
	8	M24 Q 24	icandy	18	12 Mar 2009, 14:54
	2	M24 Q 33	icandy	21	12 Mar 2009, 14:59
	1	PS: m 24 #36	pmal04	3	25 Jul 2009, 13:56

M24 #4

Moderator: Bunuel

Main navigation

GMAT Resources

Partners

MBA Resources

GMAT ® is a registered trademark of the Graduate Management Admission Council ® (GMAC ®). GMAT Club's website has not been reviewed or endorsed by GMAC.

GMAT Courses

Admissions Consulting

M24 #4

M24 #4

Main navigation

GMAT Resources

Partners

MBA Resources