Solution Y is 30 percent liquid X and 70 percent water. If 2 kilogram

Question

Solution Y is 30 percent liquid X and 70 percent water. If 2 kilograms of water evaporate from 8 kilograms of solutions Y and 2 kilograms of solution Y are added to the remaining 6 kilograms of liquid, what percent of this new liquid solution is liquid X?

A. 30%
B. 33 1/3%
C. 37 1/2%
D. 40%
E. 50%

A. 30%
B. 33 1/3%
C. 37 1/2%
D. 40%
E. 50%

PS20380

Bunuel · Accepted Answer

In 8 kilograms of solution Y there are 0.3*8=2.4 kilograms of solution X;

After 2 kilograms of water are replaced by 2 kilograms of solution Y, to the existing 2.4 kilograms of solution X, 0.3*2=0.6 kilograms of solution X are added, so in the new solution of 8 kilograms there are 2.4+0.6=3 kilograms of solution X, which is 3/8*100=37.5% of this new solution.

Answer: C.

iLc · Answer

At the beggining, you have 8KG of solution Y, i.e.

70% * 8KG = 5.6 KG of Water
30% * 8KG = 2.4 KG of X

2KG of water evaporate:

5.6KG - 2KG = 3.6KG of Water
2.4KG of X

2KG of liquid are added:

3.6KG + 2*0.70 = 5 KG of Water
2.4KG + 2*0.30 = 3 KG of X

So you have 3KG of X in 8KG (3 + 5) solution.
Therefore X concentration is 3/8 = 37.5%

AtifS · Answer

Answer:C
Took time to solve this one, the statement 2 kilograms of solution Y are added to the remaining 6 kilograms of liquid was confusing to me. After thinking more deeply, it was clear to me that new 2 kg of solution Y will also be 30% liquid X and 70% water, and then I was able to get the answer. That was a bit tricky and nice question.
Kudos +1 for posting the question

shrouded1 · Answer

Initially you start with 8kg of solution which has 2.4kg of X and 5.6kg of water
Post evaporation : 2.4kg of X and 3.6kg of water
Now we add back 2kg of Y --> 1.4Kg water + 0.6Kg X
So we have left 5Kg Water & 3Kg X

Percentage concentration is (3/5)*100 or 37.5%

TeamGMATIFY · Answer

The best way to solve these problems is to take one step at a time

Initial: 
8 kg Solution Y 
This means Solution X = 2.4 kg, Water = 5.6 kg

Step 2:
2 kg of water is evaporated.
Left over: Solution X = 2.4 kg and Water = 3.6 kg

Step 3: 
2 kg of Solutoin Y is added
Or, 0.6 kg of Solution X and 1.4 kg of water is added

Final:
Solution X = 3, Water = 5
% of solution X = 3/8 * 100 = 37.5%

Option C

sanabirm · Answer

30% of 8 + 30% of 2 = 3 = X
X/T= 3/8 = 0.375 =37.5%

Posted from my mobile device

ScottTargetTestPrep · Answer

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

CrackverbalGMAT · Answer

Concept: The question tests on Percentage and comprehension of the question and its inputs.
  Solution: 
 
Solution Y: 
   Liquid X =30% AND Water = 70%

8 Kg of Solution Y is taken and 2kg of Water evaporates from this.

=>8kg of Y has 30%of 8kg= 2.4 kg of liquid X originally in it

2kg of Y that evaporated had 30% of 2kg or 0.6kg of liquid X in it
 
 The same is added back

=> 0.6 kg of liquid X  that evaporated is added back to Y

Q. stem- We have to calculate the new percentage of liquid X in this solution(originally it was 30%)

This should be the "new" weight of liquid X in the solution/ Total weight of the solution *100

=(2.4+0.6) / 8

=3/8 *100

= 37.5%  (option c)

Devmitra Sen
GMAT SME

achloes · Answer

I read somewhere that key to solving such questions quickly is to calculate only the ratio or the weight of the ingredient of interest, which for this particular question is liquid X.

The question is asking for the ratio of liquid X to the total solution.

Old solution:
30% of liquid X in 8 kilos of solution = 2.4 kilos

New solution that is being added to old solution:
30% of liquid X in 2 kilos of solution = 0.6 kilos

Liquid X in final solution: 2.4+0.6 = 3 kilos 
Total amount of final solution: 8 - 2 + 2 = 8 kilos

3/8 = 37.5

danymasri98 · Answer

Way to go GMAC, making this problem needlessly confusing when they could've just precised that they add back 2 kgs of the original Y solution.
Somehow quant reasoning skills include deciphering confusing prompts... BS

DanTheGMATMan · Answer

Don't even worry about the water. Keep track of how much liquid x you add and you know the total is going back to 8 kg:

https://www.youtube.com/watch?v=RCCatzW1a1k

egmat · Answer

In this problem, you're dealing with evaporation AND adding more solution, which means tracking multiple moving parts. Let me walk you through this step-by-step so you can see exactly what's happening.

Here's how to think about this problem:

Step 1: Figure out what you're starting with

You begin with 8 kg of solution Y. Since solution Y is 30% liquid X and 70% water, let's break down those 8 kg:
 
 Liquid X =  0.30 	imes 8 = 2.4  kg 
 Water =  0.70 	imes 8 = 5.6  kg

Step 2: Track what happens when water evaporates

Here's the critical insight you need to catch: when 2 kg of water evaporate,  only the water leaves —the liquid X doesn't evaporate at all. This is the key to solving the problem correctly.

So after evaporation:
 
 Liquid X = still 2.4 kg (unchanged!) 
 Water =  5.6 - 2 = 3.6  kg 
 Total = 6 kg

Step 3: Add 2 kg of fresh solution Y

Now you're adding 2 kg of solution Y, which again is 30% liquid X and 70% water:
 
 This adds:  0.30 	imes 2 = 0.6  kg of liquid X 
 This adds:  0.70 	imes 2 = 1.4  kg of water

Your final mixture:
 
 Liquid X =  2.4 + 0.6 = 3.0  kg 
 Water =  3.6 + 1.4 = 5.0  kg 
 Total = 8 kg

Step 4: Calculate the final percentage

Percentage of liquid X =  \frac{3.0}{8.0} 	imes 100\% = \frac{3}{8} 	imes 100\% = 37.5\% = 37\frac{1}{2}\%

Answer: C (371⁄2%)

Notice how the percentage increased from the original 30% to 371⁄2%? That makes sense because you removed pure water (which concentrated the solution) and then added back solution that maintained some of that concentration.

While this walkthrough gets you to the right answer, there's a lot more to mastering mixture problems like this one. The systematic framework for tackling  any  sequential mixture problem, the common traps students fall into (like misunderstanding what actually evaporates), and the time-saving patterns you can apply to similar questions—all of this is covered in detail on Neuron.

You can check out the  complete solution and framework on Neuron by e-GMAT  to see the full breakdown of common mistakes and the strategic approach that works across all mixture problems. You can also explore  other GMAT official questions with detailed solutions on Neuron  for structured practice that builds your pattern recognition skills.

Hope this helps!

AKSAAA · Answer

how to get OG filter in questions bank

egmat · Answer

AKSAAA  If you're talking about  Neuron's question bank , then you can filter under "source" by Official guide or mock. So, if you want questions for OG only, just select official guide. Find the screenshot attached for further reference.

Hope this helps.

https://i.ibb.co/B5bPzpDJ/Screenshot-17-10-2025-162923-neuron-e-gmat-com.jpg

Solution Y is 30 percent liquid X and 70 percent water. If 2 kilogram

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GMAT Problem Solving (PS) Questions

Solution Y is 30 percent liquid X and 70 percent water. If 2 kilogram

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards