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

Redeem

If a certain concrete mixture contains gravel, water, and

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
Legendary Member
Posts: 2499
Joined: Sun Oct 29, 2017 2:04 pm
Followed by:6 members

by swerve » Wed Jan 16, 2019 10:21 am
We can solve this question as follows,

1X + 3X + 5X = 72
9X = 72
X=8.

Hence, E is the correct answer.
Top

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pm
Location: Palo Alto, CA
Thanked: 2867 times
Followed by:511 members
GMAT Score:800

by [email protected] » Wed Jan 16, 2019 10:42 am
Hi All,

We're told that a certain concrete mixture contains gravel, water, and sand in a ratio of 1 to 3 to 5 by weight. We're asked for the number of pounds of gravel that would be needed to produce 72 pounds of the mixture. This math behind this question can be approached in a number of different ways (depending on how you want to work through your calculations).

To start, a ratio of 1:3:5 means that for every 1 pound of gravel, we'll need 3 pounds of water and 5 pounds of sand. In essence, for every 1+3+5 = 9 pounds of this mixture, 1 pound of it will be gravel.

With 72 total pounds, we have 72/9 = 8 'sets' of the 1:3:5 mixture described), so we would have 8(1) = 8 pounds of gravel, 8(3) = 24 pounds of water and 8(5) = 40 pounds of sand. You'll notice that all 3 of those numbers are in the answer choices; we're asked for the number of pounds of GRAVEL though...

Final Answer: E

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8085
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

by Scott@TargetTestPrep » Mon Jan 21, 2019 5:49 pm
AAPL wrote:Princeton Review

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 the mixture?

A. 72
B. 40
C. 24
D. 9
E. 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.

Answer: E

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