In 2020 Ricky spent their entire back-to-school allowance on 10 shirts and 6 pairs of pants, with the price of each shirt being $20. The next year in 2021 the price of shirts dropped to $10, the price of pants remained the same, and now Ricky spent the same allowance on 15 shirts and 8 pairs of pants. Solve for Ricky's budget and the price of each pair of pants. Then graph Ricky's budget constraint in 2020, with the number of purchased pairs of pants on the x-axis and the number of purchased shirts on the y-axis