First, determine the difference between the amount Percy paid and the price of the basketball. That is, $24.10 - $22.99 = $1.11. Divide this value by the price of the basketball and multiply the quotient by 100% to get the tax rate.
($1.11 / $22.99) x 100% = 4.8%
Thus, the sales tax is approximately equal to 4.8%.