To represent the problem with a system of equations, we can define the variables as follows:
- Let \( x \) be the price of a cookie.
- Let \( y \) be the price of a brownie.
Now we can set up the equations based on the information given in the problem:
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Betty's Purchase: Betty bought 6 cookies and 5 brownies for a total of $38. This can be represented by the equation: \[ 6x + 5y = 38 \]
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Duncan's Purchase: Duncan bought 2 cookies and 3 brownies for a total of $18. This can be represented by the equation: \[ 2x + 3y = 18 \]
So, the system of equations is: \[ \begin{align*} 6x + 5y &= 38 \quad \text{(1)} \ 2x + 3y &= 18 \quad \text{(2)} \end{align*} \]