BTGmoderatorLU wrote:Source: 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 of the mixture?

A. 72
B. 40
C. 24
D. 9
E. 8

The OA is E

Given the concrete mixture contains gravel, water, and sand in a 1 to 3 to 5 ratio by weight, the weight of the mixture would be 1 + 3 + 5 = 9 lbs.

To produce 72 pounds of the mixture, we will need 72*(1/9) = 8 lbs of gravel.

The correct answer: E

Hope this helps!

-Jay
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BTGmoderatorLU wrote:Source: 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 of the mixture?

A. 72
B. 40
C. 24
D. 9
E. 8

The OA is E

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 needed is 8.

Answer: E