If a watch costs $40 and you must pay 6.5 % sales tax, how much will the tax be?

To calculate the sales tax on a watch that costs $40 with a sales tax rate of 6.5%, you can use the following formula:

\[ \text{Sales Tax} = \text{Cost} \times \left(\frac{\text{Tax Rate}}{100}\right) \]

Substituting the values:

\[ \text{Sales Tax} = 40 \times \left(\frac{6.5}{100}\right) \]

Calculating the tax:

\[ \text{Sales Tax} = 40 \times 0.065 = 2.6 \]

So, the sales tax will be $2.60.