To set up the system of equations correctly based on the problem statement, we need to define the following variables:
- Let \( x \) be the number of items sold for $4.50.
- Let \( y \) be the number of items sold for $6.00.
- Let \( z \) be the number of items sold for $7.50.
Based on the information given:
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Total items sold: The vendor sold a total of 87 items, which can be expressed as: \[ x + y + z = 87 \]
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Total revenue: The total revenue from all sold items is $489, which can be expressed as: \[ 4.5x + 6y + 7.5z = 489 \]
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Relationship between y and z: The vendor sold 5 more items for $6.00 than for $7.50, which can be expressed as: \[ y = z + 5 \quad \text{(or equivalently)} \quad z = y - 5 \]
Putting this all together, the correct system of equations is:
- \( x + y + z = 87 \)
- \( 4.5x + 6y + 7.5z = 489 \)
- \( y = z + 5 \)
Therefore, the appropriate choice from the options provided is: \[ x + y + z = 87 \] \[ 4.5x + 6y + 7.5z = 489 \] \[ y = z + 5 \]