Hi All,
We're told that a certain mixture of paint requires blue, yellow, and red paints in ratios of 2:3:1, respectively, and no other ingredients - and that there are ample quantities of the blue and red paints available. We're asked if there is enough of the yellow paint to make the desired amount of the mixture. This is a YES/NO question.
To start, when dealing with ratio questions, it's important to recognize the 'relationships' among the items in the ratio. Here, with a ratio of 2:3:1, we know that for every 2 quarts of blue, we would need 3 quarts of yellow and 1 quart of red. Often, ratios are based on integers (for example, you can't have a 'fraction' of a person); here though, 'fractional' amounts ARE possible as long as the ratio is maintained.
1) Exactly 20 quarts of the mixture are needed.
With the information in Fact 1, we CAN determine exactly how much of each paint is required (and since yellow paint represents 3 out of every 6 'parts' of the ratio, we know that a 20 quart mixture would require 10 quarts of yellow paint). However, we don't have enough information to answer the question that is ASKED.
Fact 1 is INSUFFICIENT
2) Exactly 10 quarts of the yellow paint are available.
Fact 2 tells us how much yellow paint is available, but not how much is actually NEEDED.
Fact 2 is INSUFFICIENT
Combined, we know:
-The amount of yellow paint that is needed (10 quarts)
-The amount of yellow paint that is available (10 quarts)
Thus, we CAN answer the question - and it is ALWAYS YES.
Combined, SUFFICIENT.
Final Answer: C
GMAT assassins aren't born, they're made,
Rich
