GRE Prep 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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
A nurse is combining one solution with an 8% concentration of acid in
[#permalink]
07 Jun 2021, 05:00
07 Jun 2021, 05:00
Expert Reply
00:00
Question Stats:
87% (01:51) correct
12% (02:49) wrong based on 24 sessions
Hide Show timer Statistics
A nurse is combining one solution with an 8% concentration of acid in water with another solution that has a 15% concentration of acid in water. If the nurse uses 120 ml of the 8% solution, what volume of the 15% solution should be used to obtain a mixture with 12% concentration?
Show: :: OA
160 ml
Retired Moderator
Joined: 16 Apr 2020
Status:Founder & Quant Trainer
Affiliations: Prepster Education
Posts: 1546
Given Kudos: 172
Location: India
WE:Education (Education)
Re: A nurse is combining one solution with an 8% concentration of acid in
[#permalink]
07 Jun 2021, 06:03
07 Jun 2021, 06:03
2
Carcass wrote:
A nurse is combining one solution with an 8% concentration of acid in water with another solution that has a 15% concentration of acid in water. If the nurse uses 120 ml of the 8% solution, what volume of the 15% solution should be used to obtain a mixture with 12% concentration?
Show: :: OA
160 ml
\(0.08x + 0.15y = 0.12(x+y)\)
\(8x + 15y = 12x + 12y\)
\(3y = 4x\)
\(y = \frac{4x}{3}\)
Given \(x = 120\),
So, \(y = \frac{4(120)}{3} = 160\)
Attachments
A nurse is combining one solution with an 8% concentration.png [ 3.6 KiB | Viewed 3491 times ]
A nurse is combining one solution with an 8% concentration of acid in
[#permalink]
07 Jun 2021, 06:18
07 Jun 2021, 06:18
2
Attachment:
Capture.JPG [ 11.8 KiB | Viewed 3446 times ]
We can use the mixture shortcut to solve this within seconds.
Conc. A has 8% acid, Conc. B has 15% acid, the mixture of both of them has 12% acid.
We just have to take the differences between 12% (the mixture) and each of concentration A and B, and assign the quotient to the other concentration (look at the figure above), to get the RATIO of Volume.
So we get the ratio of volume for 8% and 15% concentration as 3 : 4
Given, the nurse uses 120 ml of the 8% solution
So the volume of 15% conc. = (120/3) * 4 = 160 (Answer)
Hope this helps!
