Hi All,
We're told that in the Dives Corporation, 75% of the employees are customer service representatives, 15% are programmers, and 10% are managers, the customer service representatives have an average salary of $60,000, and the programmers have an average salary of $100,000. We're asked if the average salary of ALL employees is also $100,000, then what is the average salary of the MANAGERS. This question can be approached in a variety of different ways - using some variation on the Average Formula. Here's how you can use the concept of a 'Weighted Average' against this prompt.
Since the average salary of ALL employees is $100,000, we can ignore the programmers (since they have an average salary of $100,000 already). This allows us to focus on the customer service representatives and the managers. 75% of the employees are customer service representatives and 10% are managers, so that is a ratio of 7.5 to 1 (meaning for every 1 manager, there are 7.5 customer service reps).
Customer service reps have an average salary of $60,000, so each rep is essentially $40,000 BELOW the average. This difference has to be 'made up' by the managers. For every 7.5 customer service reps, we'll be (7.5)($40,000) = $300,000 total below what the average is supposed to be, so the 1 manager will have to 'make up' that $300,000 AND have a $100,000 salary to match the average. This means that each manager would need to earn $300,000 + $100,000 = $400,000 to balance out the average.
Final Answer:
GMAT assassins aren't born, they're made,
Rich