Problem Solving

Hi aditiniyer,

Although the prompt does not explicitly state it, we're meant to infer that the company continues to produce products EVERY month (in the years 2005 through 2008, inclusive). A 200% increase in the monthly average (from 2005) would be 6,000 products per month for the ENTIRE 4-YEAR period.

Thus, the TOTAL number of products produced during those 4 years would have to be (48 months)(6,000 products/month) = 288,000 products.

In 2005, the total number of products produced was (12 months)(2,000 products/month) = 24,000 products.

To hit the 288,000 product grand total, the company would have to produce 288,000 - 24,000 = 264,000 products in the years 2006 - 2008.

Final Answer: D

As an aside, you actually got a bit 'lucky' with your error. If you were to see this question on the Official GMAT, it's likely that the first answer that you calculated (re: 216,000) would be among the answer choices - meaning that you would have gotten the question wrong and not even known it.

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

aditiniyer wrote:During 2005 a company produced an average of 2000 products per month.How many products will the company need to produce from 2006 through 2008 in order to increase its monthly average for the period from 2005 through 2008 by 200 % over its 2005 average ?

A) 148,000
B) 172,000
C) 200,000
D) 264,000
E) 288,000

We need to determine how many products a company will need to produce in order to increase its monthly average of 2,000 products by 200% for the period from 2005 through 2008. Thus the average has to increase to 3 x 2,000 = 6,000 products.

Since the company produced an average of 2,000 products per month in 2005, the company produced 2,000 x 12 = 24,000 products in 12 months (or in all of 2005).

We can let x = the sum of products made from 2006 through 2008, and we can let our quantity of months = 4 years x 12 months in a year = 48 months. Now let's use the average equation to determine x:

6,000 = (24,000 + x)/48

288,000 = 24,000 + x

x = 264,000

Answer: D

aditiniyer wrote:During 2005 a company produced an average of 2000 products per month.How many products will the company need to produce from 2006 through 2008 in order to increase its monthly average for the period from 2005 through 2008 by 200 % over its 2005 average ?

A) 148,000
B) 172,000
C) 200,000
D) 264,000
E) 288,000

I multiplied the monthly average of 2000 by 3 to obtain the average as 6000 products. Considering 3 years and 12 months each, I multiplied 6000 by 3 & 12 to obtain 216,000. Where am I going wrong ?

This is a typical question on the concept of weighted average.

We want that the average for 2005 to 2008 must be more by 200% of 2005 average, or we can say that it should be 300% of 2005 average. 300% means 3 times, so we want 2005 to 2008 total = (3*2000)*4*12 = 288,000.

Total number of products in 2005 = 2000*12 = 24000.

Thus, the total number of products from 2006 to 2008 = 288,000 - 24,000 = 264,000.

The correct answer: D

Hope this helps!

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