Question

In California, state sales tax rates vary by county. In Alameda County, the sales tax rate is 8 1/2%.

Answer 1

The tax is 8.5%.
To find the tax on an item, multiply 8.5% by the price of the item.

t-shirt:
8.5% of $12.99 = 8.5% * $12.99 = 0.085 * $12.99 = $1.10
The tax on the t-shirt is $1.10

pair of jeans:
8.5% of $39.99 = 8.5% * $39.99 = 0.085 * $39.99 = $3.40
The tax on the jeans is $3.40

The difference in the amount of tax is

$3.40 - $1.10 = $2.30

Answer: $2.30