well, we know she paid a total after tax of $68.37, we also know that each game had a tax of $1.29, so 3 games that'll be 3 * 1.29 = 3.87.
so if we take out the tax from 68.37, that'll be 68.37 - 3.87 = 65 bucks.
we know each game cost the same amount so 65 ÷ 3 ≈ 21.67 before tax.