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Zorluk: OrtaSystems of Linear Equations

A freight logistics company charges fixed rates per unit for two types of cargo containers: Type XX and Type YY. Shipping 44 Type XX containers and 33 Type YY containers costs a total of $290\$290. Shipping 66 Type XX containers and 55 Type YY containers costs a total of $460\$460. Based on these rates, what is the total cost to ship 77 Type XX containers and 66 Type YY containers?

  1. A
    $375
  2. B
    $495
  3. $545Cevap
  4. D
    $630
  5. E
    $750

Cevap

$545
By solving the system 4x+3y=2904x + 3y = 290 and 6x+5y=4606x + 5y = 460, subtracting the first equation from the second yields 2x+2y=1702x + 2y = 170, so x+y=85x + y = 85. Adding x+y=85x + y = 85 to 6x+5y=4606x + 5y = 460 gives 7x+6y=5457x + 6y = 545. Alternatively, solving individually yields x=35x = 35 and y=50y = 50, giving 7(35)+6(50)=5457(35) + 6(50) = 545.

Adım Adım Çözüm

1
Set up a system of linear equations representing the given shipping costs.
Let xx be the cost per Type XX container and yy be the cost per Type YY container. Equation (1): 4x+3y=2904x + 3y = 290. Equation (2): 6x+5y=4606x + 5y = 460.
Translate the word problem statements into linear equations.
2
Subtract Equation (1) from Equation (2) to find a linear combination.
(6x + 5y) - (4x + 3y) = 460 - 290 \implies 2x + 2y = 170 \implies x + y = 85.
Determining the combined cost of one container of each type simplifies calculating larger combinations.
3
Add the expression for x+yx + y to Equation (2) to obtain 7x+6y7x + 6y.
(6x + 5y) + (x + y) = 460 + 85 \implies 7x + 6y = 545.
Combining 6x+5y6x + 5y and x+yx + y directly gives the cost for 77 Type XX and 66 Type YY containers without requiring individual variable solving.

Anahtar Kavram

Linear combinations and systems of linear equations in two variables
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