A car wash business charges $10 per basic wash and $15 per ultimate wash. The total sales was $980 on a certain day. The variable x represents the number of basic washes and y represents the number of uitimate washes

The equation models this situation 10x+15y=980 Where x represents number of basic washes and y represents the number of ultimate washes. For total sales we want to add the two basic given data. Therefore basic wash and ultimate wash which is equal to total sales on that day.