Tax value = 3.60 tax rate = 5% to solve for the tax value, we use this formula: tax value = original price * tax rate since the original price is missing, we derive the formula from the above formula: original price = tax value ÷ tax rate original price = 3.60 ÷ 5% original price = 72 the original price is 72. 72 x 5% = 3.60