Combination problem

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Combination problem

by datonman » Tue Mar 31, 2015 9:23 am
This was quite a question for me:

The local baseball team employs at least 3 times as many pitchers as catchers, but never more than 11 players total. Pitches make an average of $45,000, and catchers make an average of $30,000. Which of the following amounts are the possible averages for all the pitchers and catchers, rounded to the nearest dollar?

A.)30,000
B.)35,899
C.)40,375
D.)41,250
E.)41,956
F.)42,273
G.)43,743
H.)45,000

Now for those of you trying to figure this problem out, you can probably guess where I got it from. I'm not looking for the answer just so much as the process of 'getting' to the answer.

For instance, there's a solution that suggests that the only combination of pitchers and catchers that apply are "3 pitchers and 1 catcher and 6 pitchers and 2 catchers." The question to me does not point out or imply anything relating to 4 or 8.(Again, from what I can tell.) Is there a way on how this solution is possible? Better yet, is there a different solution overall?
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by [email protected] » Wed Apr 01, 2015 1:19 pm
Hi datonman,

From a tactical standpoint, the 'key' to dealing with this prompt is to focus on how Weighted Averages "work." You can also save some time and energy by removing most of the the "zeros" from the equations and thinking about the minimum and maximum possible averages.

As a hypothetical, imagine that you had 1 pitcher and 1 catcher. What would the average salary be.....?

(45 + 30)/2 = 37.5 or $37,500

As you increase the number of pitchers (relative to the number of catchers), the average INCREASES (since pitchers make more money than catchers).

To find the minimum average ....calculate the average when there are 3 pitchers and 1 catcher.

The prompt also states that the there are AT LEAST 3 times as many pitchers as catchers....but no more than 11 players total...

To find the maximum average ...calculate the average when there are 10 pitchers and 1 catcher.

In theory, every number between (and including) the minimum and maximum values is a possible answer. HOWEVER, there's still the very real possibility that an answer might be between the minimum and maximum but NOT actually be a number that the average could equal. That's not likely to occur in this type of option, but you might have to try to 'target' a specific answer (using Number Properties) to see if you can prove that it's a possibility.

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