If the original price of the football is $22.00, and the store is offering a 20% discount, then the new price of the football before tax would be:
New price before tax = Original price - Discount
= $22.00 - (20% x $22.00)
= $17.60
Now, we need to calculate the price of the football after adding the sales tax of 5%. To do this, we can calculate the amount of sales tax first, and then add it to the new price before tax:
Sales tax = 5% x $17.60
= $0.88
Price after tax = New price before tax + Sales tax
= $17.60 + $0.88
= $18.48
Therefore, the cost of the discounted football after tax is $18.48.