Final answer:
The question is about computing sales tax for purchases made in different states. The calculation involves converting the percentage to a decimal format and then multiplying by the item's cost. For purchases made by Kalani and Nick, their total costs including sales tax would be $1,495.90 and $2,616.00, respectively.
Step-by-step explanation:
The question involves applying the concept of calculating sales tax on purchases, which is a topic under the subject of Mathematics, typically covered at the High School level. To calculate the sales tax for each individual, the tax rates provided must be converted to decimal form and then multiplied by the cost of the items. For Kalani's purchase in Utah, the calculation would be $1,400 times 0.0685 (6.85% as a decimal), resulting in a sales tax of $95.90. Therefore, the total cost including tax would be $1,495.90. In the case of Nick in Alabama, the sales tax would be $2,400 times 0.09 (9% as a decimal), equating to $216.00 in tax, making the total cost including tax $2,616.00.