Let \( x \) be the number of hot dogs sold and \( y \) be the number of pretzels sold.
We have the following two equations based on the problem description:
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Total items sold: \[ x + y = 300 \]
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Total income generated: \[ 4x + 2y = 800 \]
Now, we can solve this system of equations.
First, we can simplify the second equation by dividing everything by 2: \[ 2x + y = 400 \]
Now we have the simplified system:
- \( x + y = 300 \)
- \( 2x + y = 400 \)
Next, we can subtract the first equation from the second: \[ (2x + y) - (x + y) = 400 - 300 \] \[ 2x + y - x - y = 100 \] \[ x = 100 \]
Now that we found \( x \), we can substitute it back into the first equation to find \( y \): \[ 100 + y = 300 \] \[ y = 300 - 100 \] \[ y = 200 \]
Thus, the boosters need to sell:
- Hot dogs: \( \mathbf{100} \)
- Pretzels: \( \mathbf{200} \)
To verify, we can check the income:
- Income from hot dogs: \( 100 \times 4 = 400 \)
- Income from pretzels: \( 200 \times 2 = 400 \)
- Total income: \( 400 + 400 = 800 \), which matches the goal.
Therefore, the final answer is: They need to sell 100 hot dogs and 200 pretzels.