You know that the popcorn cost $5.00 so the drinks would cost $2.50 each. So when you plot the points you would reach $10.00 for popcorn and have $5.00 for drinks. $15.00 for popcorn and $7.50 for drinks.
Explanation:
Judy has $30 to spend.
The price per bag of popcorn is $5.
The price per drink is $2.50.
is your equation