Final answer:
To find the sales tax percentage on an $800 antique clock that costs $840 with tax, subtract the original price from the total to discover the tax amount ($40), then divide by the original price and multiply by 100 to find a 5% sales tax. The sales tax percentage is 5%.
Step-by-step explanation:
To calculate the sales tax percentage of an $800 antique clock that costs $840 with tax, you first subtract the original price from the total price to find the amount of sales tax paid.
This gives you $840 - $800 = $40.
Next, you convert the sales tax amount to a percentage of the original price by dividing the sales tax by the original price: $40 ÷ $800 = 0.05.
Finally, to get the percentage, you multiply by 100: 0.05 × 100 = 5%.
Therefore, the sales tax percentage is 5%.