GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 21 Oct 2019, 15:47

### 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

# In a certain solution, the ratio of water to alcohol is 3:1. If water

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58396
In a certain solution, the ratio of water to alcohol is 3:1. If water  [#permalink]

### Show Tags

22 Jan 2019, 02:19
00:00

Difficulty:

45% (medium)

Question Stats:

62% (01:27) correct 38% (01:21) wrong based on 49 sessions

### HideShow timer Statistics

In a certain solution, the ratio of water to alcohol is 3:1. If water and alcohol combined make up half of the volume of the solution, what percentage of the solution is water?

A 12.5%
B 25%
C 37.5%
D 50%
E 75%

_________________
GMAT Club Legend
Joined: 18 Aug 2017
Posts: 5027
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: In a certain solution, the ratio of water to alcohol is 3:1. If water  [#permalink]

### Show Tags

22 Jan 2019, 05:46
1
Bunuel wrote:
In a certain solution, the ratio of water to alcohol is 3:1. If water and alcohol combined make up half of the volume of the solution, what percentage of the solution is water?

A 12.5%
B 25%
C 37.5%
D 50%
E 75%

water : alcohol ; 3:1

let total vol ; 100
half ; 50
3*50 / 4 = 37.5%
IMO C
Senior SC Moderator
Joined: 22 May 2016
Posts: 3565
Re: In a certain solution, the ratio of water to alcohol is 3:1. If water  [#permalink]

### Show Tags

22 Jan 2019, 15:41
Bunuel wrote:
In a certain solution, the ratio of water to alcohol is 3:1. If water and alcohol combined make up half of the volume of the solution, what percentage of the solution is water?

A 12.5%
B 25%
C 37.5%
D 50%
E 75%

Use totals of ratio parts. We need nothing else.

We have two "halves" of a solution. One half contains only water and alcohol.
The other half contains some liquid other than water and alcohol (mercury or oil, e.g.)

• The water-and-alcohol portion: from its ratio parts, derive total parts of that portion

W : A : TOTAL parts
$$3 : 1 : 4$$
Total parts = $$(3 + 1) = 4$$

(Water is 3 of 4 parts. Alcohol is 1 of 4 parts. The concentration here does not matter.
We need total volume, total parts, of the whole amount of the solution.
We use the water/alcohol ratio to calculate what amount "half" of the solution equals.)

• The entire solution contains how many parts?

The 4 parts of water-and-alcohol make up only half of all the liquid in the solution

If 4 parts =$$\frac{1}{2}$$ of total parts in the solution, then
8 parts = total number of parts in the solution

The number of parts of water does not change.

• Water is what percentage of the solution [the solution made up of 8 parts]?

Water = 3 parts of 8 parts

Percentage: $$\frac{Part}{Whole}* 100$$

$$\frac{3}{8} = .375 * 100 = 37.5$$

_________________
SC Butler has resumed! Get two SC questions to practice, whose links you can find by date, here.

Instructions for living a life. Pay attention. Be astonished. Tell about it. -- Mary Oliver
Re: In a certain solution, the ratio of water to alcohol is 3:1. If water   [#permalink] 22 Jan 2019, 15:41
Display posts from previous: Sort by