swerve wrote:Ayayai electronics is a company manufacturing MP3 players. Ayayai manufactures only two players: iMe and iMine. Either player is assembled using a LCD screen or an OLED screen. Excluding the expensive OLED-iMine model, Ayayai manufactures 21,000 players per month. Every month, Ayayai manufactures 11,000 players with an OLED screen, and 12,000 iMine models. If Ayayai manufactures 8000 LCD iMe models monthly, how many players (of all models) does Ayayai manufacture per month?

A. 24,000
B. 25,000
C. 26,000
D. 27,000
E. 28,000

The OA is C

Source: Economist GMAT

See this image.



Thus, (1,000 + x) + x = 11,000

=> x = 5,000

Thus, total number of players = 21,000 + x = 21,000 + 5,000 = 26,000.

The correct answer: C

Hope this helps!

-Jay
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I thought I'd point out that Jay's approach is known as the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it.

Here, we have a population of MP3 players, and the two characteristics are:
- iMe or iMine
- LCD screen or OLED screen

This question type is VERY COMMON on the GMAT, so be sure to master the technique.

To learn more about the Double Matrix Method, watch this video: https://www.gmatprepnow.com/module/gmat- ... ems?id=919

Once you're familiar with this technique, you can attempt these additional practice questions:

Easy Problem Solving questions
- https://www.beatthegmat.com/finance-majo ... 67425.html

Medium Problem Solving questions
- https://www.gmatprepnow.com/module/gmat- ... /video/920
- https://www.beatthegmat.com/posted-speed ... 72374.html
- https://www.beatthegmat.com/motel-t271938.html
- https://www.beatthegmat.com/of-the-appli ... 70255.html
- https://www.beatthegmat.com/opening-nigh ... 64869.html
- https://www.beatthegmat.com/at-least-100 ... 74669.html
- https://www.beatthegmat.com/prblem-solving-t279424.html

Difficult Problem Solving questions
- https://www.gmatprepnow.com/module/gmat- ... /video/946
- https://www.beatthegmat.com/ratio-problem-t268339.html
- https://www.beatthegmat.com/overlapping- ... 65223.html
- https://www.beatthegmat.com/fractions-t264254.html
- https://www.beatthegmat.com/overlapping- ... 64092.html
- https://www.beatthegmat.com/mba/2011/05/ ... question-2

Easy Data Sufficiency questions
- https://www.gmatprepnow.com/module/gmat- ... /video/943
- https://www.beatthegmat.com/for-what-per ... 70596.html
- https://www.beatthegmat.com/ds-quest-t187706.html

Medium Data Sufficiency questions
- https://www.beatthegmat.com/sets-matrix-ds-t271914.html
- https://www.beatthegmat.com/each-of-peop ... 71375.html
- https://www.beatthegmat.com/a-manufacturer-t270331.html
- https://www.beatthegmat.com/in-costume-f ... 69355.html
- https://www.beatthegmat.com/mba/2011/05/ ... question-1

Difficult Data Sufficiency questions
- https://youtu.be/dsCeqF9Kbk8
- https://www.beatthegmat.com/double-set-m ... 71423.html
- https://youtu.be/dOZ9KM1m5Hs
- https://www.beatthegmat.com/sets-t269449.html
- https://www.beatthegmat.com/mba/2011/05/ ... question-3

Cheers,
Brent

swerve wrote:Ayayai electronics is a company manufacturing MP3 players. Ayayai manufactures only two players: iMe and iMine. Either player is assembled using a LCD screen or an OLED screen. Excluding the expensive OLED-iMine model, Ayayai manufactures 21,000 players per month. Every month, Ayayai manufactures 11,000 players with an OLED screen, and 12,000 iMine models. If Ayayai manufactures 8000 LCD iMe models monthly, how many players (of all models) does Ayayai manufacture per month?

A. 24,000
B. 25,000
C. 26,000
D. 27,000
E. 28,000

The OA is C

Source: Economist GMAT

We can let x = the number of OLED-iMine model players, y = the number of OLED-iMe model players, z = the number of LCD-iMine model players, and w = the number of LCD-iMe model players. We need to find the value of x + y + z + w.

We are given the following:

y + z + w = 21,000

x + y = 11,000

x + z = 12,000

and

w = 8,000

Substituting w = 8,000 into the first equation, we have y + z + 8,000 = 21,000, or y + z = 13,000.

Adding the equations for y + z, x + y, and x + z, we get:

y + z + x + y + x + z = 2(x + y + z) = 13,000 + 11,000 + 12,000 = 36,000.

Thus, x + y + z = 18,000. Adding w = 8,000, we obtain x + y + z + w = 26,000.

Answer: C