Bunuel wrote:

A major airplane manufacturer announced the sale of 150 small airliners at $125 million each, 75 medium sized airliners at $175 million each, and 60 large airliners at $220 million each. What percentage of the company's income came from large and medium airliners?

A. 29%

B. 41%

C. 58%

D. 69%

E. 70%

Kudos for a correct solution.

Since you need company's income from large + medium airliners, you can find the average price of these two so that you have one less unit to work with.

Average of 175 and 220 when weights are 75 and 60 respectively (i.e. a ratio of 5:4) - Using scale method, split 45 into 5:4, you will get 25 and 20. So average will be 20 more than 175 i.e. at 195. So you have 135 airliners of price 195.

If you are lost here, check scale method:

http://www.veritasprep.com/blog/2011/03 ... -averages/ Company's income from these 135 airliners \(= \frac{135*195}{(135*195 + 150*125)} = \frac{27*39}{(27*39 + 150*5)} = \frac{9*39}{(9*39 + 250)} = 58%\)

Answer (C)

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Karishma

Veritas Prep GMAT Instructor

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