It is currently 17 Oct 2017, 21:20

### 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

# Some part of the 50% solution of acid was replaced with the

Author Message
Manager
Joined: 21 Feb 2008
Posts: 87

Kudos [?]: 22 [0], given: 2

Schools: UCLA Anderson '12
Some part of the 50% solution of acid was replaced with the [#permalink]

### Show Tags

21 Oct 2008, 11:41
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Some part of the 50% solution of acid was replaced with the equal amount of 30% solution of acid. As a result, 40% solution of acid was obtained. What part of the original solution was replaced?

A. $$\frac{1}{5}$$

B. $$\frac{1}{4}$$

C. $$\frac{1}{2}$$

D. $$\frac{3}{4}$$

E. $$\frac{4}{5}$$

Answer is C. It's relatively easy to understand why 1/2 is correct but I can't logically put an equation together to solve the question.

Kudos [?]: 22 [0], given: 2

SVP
Joined: 07 Nov 2007
Posts: 1792

Kudos [?]: 1058 [0], given: 5

Location: New York

### Show Tags

21 Oct 2008, 13:16
duuuma wrote:
Some part of the 50% solution of acid was replaced with the equal amount of 30% solution of acid. As a result, 40% solution of acid was obtained. What part of the original solution was replaced?

A. $$\frac{1}{5}$$

B. $$\frac{1}{4}$$

C. $$\frac{1}{2}$$

D. $$\frac{3}{4}$$

E. $$\frac{4}{5}$$

Answer is C. It's relatively easy to understand why 1/2 is correct but I can't logically put an equation together to solve the question.

x is part of solution replaced

0.5 (1-x) +0.3*x = 0.4*1

x=1/2
_________________

Smiling wins more friends than frowning

Kudos [?]: 1058 [0], given: 5

SVP
Joined: 29 Aug 2007
Posts: 2472

Kudos [?]: 842 [0], given: 19

### Show Tags

21 Oct 2008, 14:10
0.5 (1-X) + 0.3X = 0.4
X = 1/2

CANNOT ADD ANYTHING TO ABOVE SOL.
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Kudos [?]: 842 [0], given: 19

Manager
Joined: 21 Feb 2008
Posts: 87

Kudos [?]: 22 [0], given: 2

Schools: UCLA Anderson '12

### Show Tags

21 Oct 2008, 14:48
Not sure I understand your comment. What do you mean by, "cannot add anything..."?
GMAT TIGER wrote:
0.5 (1-X) + 0.3X = 0.4
X = 1/2

CANNOT ADD ANYTHING TO ABOVE SOL.

Kudos [?]: 22 [0], given: 2

SVP
Joined: 29 Aug 2007
Posts: 2472

Kudos [?]: 842 [0], given: 19

### Show Tags

21 Oct 2008, 16:39
duuuma wrote:
Not sure I understand your comment. What do you mean by, "cannot add anything..."?
GMAT TIGER wrote:
0.5 (1-X) + 0.3X = 0.4
X = 1/2

CANNOT ADD ANYTHING TO ABOVE SOL.

I meant "CANNOT ADD ANYTHING TO THE ABOVE SOL.by "x2suresh". Is it clear now, "duuuma"?
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Kudos [?]: 842 [0], given: 19

Manager
Joined: 21 Feb 2008
Posts: 87

Kudos [?]: 22 [0], given: 2

Schools: UCLA Anderson '12

### Show Tags

21 Oct 2008, 16:49
I'm guessing you meant that you agree with his solution and cannot add anything on top of that? Makes sense - thanks

GMAT TIGER wrote:

I meant "CANNOT ADD ANYTHING TO THE ABOVE SOL.by "x2suresh". Is it clear now, "duuuma"?

Kudos [?]: 22 [0], given: 2

SVP
Joined: 29 Aug 2007
Posts: 2472

Kudos [?]: 842 [0], given: 19

### Show Tags

21 Oct 2008, 18:31
duuuma wrote:
I'm guessing you meant that you agree with his solution and cannot add anything on top of that? Makes sense - thanks

GMAT TIGER wrote:

I meant "CANNOT ADD ANYTHING TO THE ABOVE SOL.by "x2suresh". Is it clear now, "duuuma"?

you got it, duuuma.
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Kudos [?]: 842 [0], given: 19

Re: Difficult Ratio question   [#permalink] 21 Oct 2008, 18:31
Display posts from previous: Sort by