Erica earns a rebate each month on her meals and movie tickets. She earns $3 for each movie ticket and $0.80 for each meal. Last month Erica purchased 15 meals and earned $18.

Part A: Create an equation that will determine the number of movie tickets she purchased. (3 points)

Part B: Solve this equation justifying each step with an algebraic property of equality. (6 points)

Part C: How many movie tickets did Erica purchase last month?