Solving the system of equations, it is found that 120 cups of lemonade and 160 brownies were sold.
<h3>What is a system of equations?</h3>
A system of equations is when two or more variables are related, and equations are built to find the values of each variable.
The variables are given as follows:
- Variable x: Number of cups of lemonade sold.
- Variable y: Number of brownies sold.
In this problem, the system is:
From the first equation, y = 280 - x, hence, replacing in the second:
2.5x + 1.5y = 540
2.5x + 1.5(280 - x) = 540
x = 540 - 1.5 x 280
x = 120
y = 280 - x = 280 - 120 = 160.
120 cups of lemonade and 160 brownies were sold.
More can be learned about a system of equations at brainly.com/question/24342899
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