What would the total cost be including tax for an item priced at $9.78?

To find the total cost of an item including tax, you first need to understand the sales tax rate applicable in your area. For the example presented, assuming a sales tax rate of 7%, the calculation would go as follows:

1. Calculate the sales tax on the item. Multiply the price of the item by the sales tax rate:

$9.78 * 0.07 = $0.6856, which rounds to approximately $0.69.

2. Add that sales tax amount to the original price of the item:

$9.78 + $0.69 = $10.47.

However, it's essential to confirm the actual tax rate used in calculations, as it may vary by location and the specific context of the question. The correct choice reflects the expected output of such a calculation when rounding numbers appropriately and ensures clarity for those calculating total costs in similar contexts.

Regarding the other options, they may not align with the correct calculations based on the standard sales tax applied. It’s crucial to use precise figures and to round accordingly when dealing with financial calculations to ensure accuracy.