A clothing store is running a promotion: buy one T-shirt at the regular price of $40, get a second T-shirt at a 20% discount, a third T-shirt at a 30% discount, and a fourth T-shirt at a 40% discount. Alex purchased four T-shirts using this promotion. What percentage of the total regular price did he save?
20%
22.5%
25%
27.5%
30%
