28 * .25 = 7
He can take $7 dollars off the price of the shirt. That is the discount
28 -7 = 21
The sale price is $21.00
21*.08 =1.68
He will pay$1.68 in sales tax
21+1.68 = 22.68
The total cost of the shirt plus the sales tax is $22.68
24 - 22.68 = 1.32
He will have $1.32 left in his wallet after buying the shirt, so he has enough money