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Zorluk: OrtaSystems of Linear Inequalities in Two Variables

A graphic designer is exporting images for a website. There are two types of images: standard images and high-resolution images. Each standard image, xx, requires 3 megabytes (MB) of storage and takes 2 seconds to upload. Each high-resolution image, yy, requires 8 MB of storage and takes 5 seconds to upload. The designer must limit the total storage of the exported images to at most 120 MB and the total upload time to at least 60 seconds. Which of the following systems of inequalities models this situation?

  1. A
    3x+2y1203x + 2y \leq 120
    8x+5y608x + 5y \geq 60
  2. B
    3x+8y1203x + 8y \geq 120
    2x+5y602x + 5y \leq 60
  3. C
    8x+3y1208x + 3y \leq 120
    5x+2y605x + 2y \geq 60
  4. 3x+8y1203x + 8y \leq 120
    2x+5y602x + 5y \geq 60
    Cevap

Cevap

The system of inequalities is 3x+8y1203x + 8y \leq 120 and 2x+5y602x + 5y \geq 60.
The correct system models the limits correctly. The storage constraint is represented by 3x+8y1203x + 8y \leq 120 since 'at most' corresponds to a less-than-or-equal-to sign. The upload time constraint is represented by 2x+5y602x + 5y \geq 60 since 'at least' corresponds to a greater-than-or-equal-to sign.

Adım Adım Çözüm

1
Set up the inequality for the storage constraint.
3x+8y1203x + 8y \leq 120
Each standard image uses 3 megabytes and each high-resolution image uses 8 megabytes. The total storage must be at most (less than or equal to) 120 megabytes.
2
Set up the inequality for the upload time constraint.
2x+5y602x + 5y \geq 60
Each standard image takes 2 seconds and each high-resolution image takes 5 seconds to upload. The total upload time must be at least (greater than or equal to) 60 seconds.
3
Combine both inequalities into a system.
The system containing 3x+8y1203x + 8y \leq 120 and 2x+5y602x + 5y \geq 60.
Both constraints must be satisfied simultaneously.

Anahtar Kavram

Translating verbal constraints into systems of linear inequalities in two variables.
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