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

 It is currently 15 Nov 2019, 06:33

### 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

# If a certain concrete mixture contains gravel, water, and sand in a 1

Author Message
TAGS:

### Hide Tags

SVP
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1701
Location: India
GPA: 3.01
WE: Engineering (Real Estate)
If a certain concrete mixture contains gravel, water, and sand in a 1  [#permalink]

### Show Tags

14 Sep 2018, 11:29
1
00:00

Difficulty:

5% (low)

Question Stats:

85% (00:45) correct 15% (00:48) wrong based on 115 sessions

### HideShow timer Statistics

If a certain concrete mixture contains gravel, water, and sand in a 1 to 3 to 5 ratio by weight, how many pounds of gravel would be needed to produce 72 pounds of the mixture?

1. 72

2. 40

3. 24

4. 9

5. 8

_________________
"Do not watch clock; Do what it does. KEEP GOING."
Intern
Joined: 02 Sep 2015
Posts: 41
Re: If a certain concrete mixture contains gravel, water, and sand in a 1  [#permalink]

### Show Tags

14 Sep 2018, 11:35
1
$$1X + 3X + 5X = 72$$
$$9X = 72$$
$$= 8$$

GMATH Teacher
Status: GMATH founder
Joined: 12 Oct 2010
Posts: 935
Re: If a certain concrete mixture contains gravel, water, and sand in a 1  [#permalink]

### Show Tags

19 Sep 2018, 19:39
AkshdeepS wrote:
If a certain concrete mixture contains gravel, water, and sand in a 1 to 3 to 5 ratio by weight, how many pounds of gravel would be needed to produce 72 pounds of the mixture?

1. 72

2. 40

3. 24

4. 9

5. 8

Trivial application of the k technique:

$$G:W:S = 1:3:5\,\,\,\,\, \Rightarrow \,\,\,\,\left\{ \matrix{ ? = G = k \hfill \cr W = 3k \hfill \cr S = 5k \hfill \cr} \right.\,\,\,\,\,\,\left( {k > 0} \right)$$

$$72 = 9k\,\,\,\, \Rightarrow \,\,\,\,? = k = {{72} \over 9} = 8\,\,\,\,\,\left[ {{\rm{pounds}}} \right]$$

This solution follows the notations and rationale taught in the GMATH method.

Regards,
fskilnik.
_________________
Fabio Skilnik :: GMATH method creator (Math for the GMAT)
Our high-level "quant" preparation starts here: https://gmath.net
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8381
Location: United States (CA)
Re: If a certain concrete mixture contains gravel, water, and sand in a 1  [#permalink]

### Show Tags

21 Jan 2019, 19:01
AkshdeepS wrote:
If a certain concrete mixture contains gravel, water, and sand in a 1 to 3 to 5 ratio by weight, how many pounds of gravel would be needed to produce 72 pounds of the mixture?

1. 72

2. 40

3. 24

4. 9

5. 8

We can create the ratio:

Gravel : water : sand = x : 3x : 5x

We can create the equation:

x + 3x + 5x = 72

9x = 72

x = 8

So the number of pounds of gravel is 8.

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Re: If a certain concrete mixture contains gravel, water, and sand in a 1   [#permalink] 21 Jan 2019, 19:01
Display posts from previous: Sort by