Tickets to an outdoor concert were $30 for front-seating and $20 for lawn seats. there were 600 more lawn seat tickets sold than front seats. sales for all the tickets totaled $30,000. samantha is making a chart to determine the total sales (in dollars) for lawn seats. she defines x as the number of front-seat tickets. which expression could samantha use on the chart to represent the total dollar sales for lawn tickets? a) 20(x + 600) b) 20(x − 600) c) 20x d) 30(x − 10)