Final answer:
Reagan received $12.20 in change.
Step-by-step explanation:
To calculate the total cost of the shirt after the discount, multiply the original price by the discount percentage (100% - 25% = 75%).
$9.75 x 0.75 = $7.31
To calculate the amount of sales tax, multiply the discounted price by the sales tax rate (6.7%).
$7.31 x 0.067 = $0.49
To calculate the total amount Reagan paid, add the discounted price and the sales tax.
$7.31 + $0.49 = $7.80
To calculate the change Reagan received, subtract the total amount paid from the $20 bill.
$20 - $7.80 = $12.20
Therefore, Reagan received $12.20 in change.