BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

500 PS

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 269
Joined: Sun Apr 01, 2007 5:41 am

500 PS

by dunkin77 » Mon Apr 02, 2007 12:19 pm
Hi,

I am having problem solving this question - could anyone explain??

Solution Y is 30 percent liquid X and 70 percent water. If 2 kilograms of water evaporate from 8 kilograms of solution Y and 2 kilograms of solution Y are added to the remaining 6 kilograms of liquid, what percent of this new solution is liquid X?
(A) 30%
(B) 33 1/3%
(C) 37 1/2%
(D) 40%
(E) 50%
Top
Source: — Problem Solving |
Junior | Next Rank: 30 Posts
Posts: 12
Joined: Tue Mar 27, 2007 2:53 pm

by vk.neni » Mon Apr 02, 2007 1:58 pm
Hi, I'm not sure if the following is the most efficient way to do it. At least for me it was quick to do this way!

in solution Y = 30% x + 70% w(ater)

So, in 8kg of Y = 2.4x + 5.6w

from this 2kg water is removed (Evaporated) so, in the remaining
6kg Y = 2.4x + 3.6w.

Now 2kg Y is added, which has 0.6x + 1.4w. So,

6kg Y = 2.4x + 3.6w.
2kg Y = 0.6x + 1.4w
-------------------------
8kg Y = 3.0x + 5.0 w

x = 3/8 * 100 = 37.5%

Answer is C
Top
Master | Next Rank: 500 Posts
Posts: 174
Joined: Mon Mar 26, 2007 5:51 am
Thanked: 1 times

by 800GMAT » Mon Apr 02, 2007 2:07 pm
I normally solve such problems by making a table.
Attachments
untitled.jpg
Top
Master | Next Rank: 500 Posts
Posts: 269
Joined: Sun Apr 01, 2007 5:41 am

by dunkin77 » Mon Apr 02, 2007 2:15 pm
It very clear and I think quicket enough! Thank you!
Top
Moderator
Posts: 772
Joined: Wed Aug 30, 2017 6:29 pm
Followed by:6 members

by BTGmoderatorRO » Sun Nov 12, 2017 12:50 pm
solution Y contains 30% (i.e 0.3) liquid X and 70% (0.7) water.
8kg of solution Y will contain = 30% liquid X in 8kg + 70% water in 8kg
=0.3 (8) kg liquid + 0.7(8) kg water
= 2.4 kg liquid X + 5.6 kg of water
Now, if 2 kg water evaporates from 8 kg of Y, we have
= 2.4 kg liquid X + (5.6-2) kg of water left.
= 2.4 kg liquid X + 3.6 kg of water
=6 kg of Y

2 kg of Y will contain,
= 30% liquid X in 2 kg + 70% of water in 2 kg
=0.3(2) kg liquid X + 0.7(2) kg water
= 0.6 kg liquid X + 1.4 kg water
Adding this to the liquid we have left, we now have = (2.4 + 0.6) kg liquid X + (3.6+1.4) kg water
=3 kg liquid X + 5 kg water
=8 kg of liquid

percentage of liquid X= $$\frac{3kg}{8kg}\cdot100\%\ =\ 37\ \frac{1}{2}\%$$ .
Hence, the correct option is C
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8087
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

by Scott@TargetTestPrep » Sat Dec 21, 2019 7:22 pm
dunkin77 wrote:Hi,

I am having problem solving this question - could anyone explain??

Solution Y is 30 percent liquid X and 70 percent water. If 2 kilograms of water evaporate from 8 kilograms of solution Y and 2 kilograms of solution Y are added to the remaining 6 kilograms of liquid, what percent of this new solution is liquid X?
(A) 30%
(B) 33 1/3%
(C) 37 1/2%
(D) 40%
(E) 50%

Originally, solution Y has 0.3 x 8 = 2.4 kg of liquid X and 0.7 x 8 = 5.6 kg of water. After 2 kg of water evaporate, solution Y has 2.4 kg of liquid X and 3.6 kg of water. However, since 2 kg of solution Y (of which, 0.3 x 2 = 0.6 kg is liquid X and 0.7 x 2 = 1.4 kg is water) are added back to the remaining 6 kilograms of solution Y, solution Y now has 2.4 + 0.6 = 3 kg of liquid X and 3.6 + 1.4 = 5 kg of water). Therefore, the percent of the new solution is liquid X is 3/(3 + 5) = 3/8 = 37.5%.

Answer: C

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Top
Post new topic Post Reply
• Page 1 of 1