According to the directions on a can of frozen orange juice concentrate, 1 can of concentrate is to be mixed with 3 cans of water to make orange juice. How many 12-ounce can of the concentrate are required to prepare 200 6-ounces serving of orange juice?
a)25
b)34
c)50
d)67
e)100

This can be solved using equivalent ratios.
The first part tells that, for every 1 can of concentrate, we can make 4 cans of juice.
Let's be even more generic, for 1 volume of concentrate, we can make 4 volumes of juice.

Okay, now notice that we have a problem with the volume mismatch in the question. It involves 12-ounce cans of concentrate and 6-ounce servings.
So, let's reword the question. Instead of making 200 6-ounce servings of juice, let's make 100 12-ounce servings of juice. We're still making the same amount of juice.

We're now asking, "How many 12-ounce cans of the concentrate are required to prepare 100 12-ounce serving of orange juice?

We'll solve this question using equivalent ratios.

(volume of concentrate)/(volume of juice): 1/4 = x/100

Solve for x to get [spoiler]x=25[/spoiler]
So, the answer is A

Cheers,
Brent

Hi NeilWatson,

This "math" behind this question can be tackled in a number of ways, as Mitch and Brent have presented. Here's another way to do it.

We're told that 1 can of concentrate needs to be mixed with 3 cans of water to make orange juice. We're told that we're dealing with 12-ounce cans.

So 1 can of concentrate (12 ounces) is mixed with 3 cans of water (3x12 = 36 ounces)...

Thus, 1 can of concentrate will lead to 12+36 = 48 ounces of orange juice.

We're asked to create 200 6-ounce servings of juice. 200x6 = 1200 total ounces of juice. We're asked how many cans of concentrate will be needed...

1200/48 = 25

Final Answer: A

GMAT assassins aren't born, they're made,
Rich