Solve the problem by writing an inequality. . . A club decides to sell T-shirts for $15 as a fundraiser. It costs $20 plus $9 per T-shirt to make the T-shirts. Write and solve an equation to find how many T-shirts the club needs to make and sell in order to profit at least $150.. 15x – (9x + 20) ≥ 150; x ≥ 28.33. 15x – 9x + 20 ≥ 150; x ≥ 20. (8x + 20) – 15x ≥ 150; x ≥ 20. 15x – 9(x + 20) ≥ 150; x ≥ 20