Final answer:
The sales tax for the things Nathan buys is $0.57.
Step-by-step explanation:
To find the sales tax for the items Nathan buys, we need to first calculate the total cost of the items. Adding together the prices of the bottle of water, gum, and book, we get $1.25 + $0.50 + $3.95 = $5.70.
Next, we need to calculate the sales tax. Since the sales tax rate is 10%, we can multiply the total cost by 0.10 to find the sales tax amount. Therefore, the sales tax for the items is $5.70 x 0.10 = $0.57.
So, the sales tax for the things Nathan buys is $0.57.