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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
OA E
If a certain concrete mixture contains gravel, water, and
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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
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
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We can create the ratio: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
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
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