What is the interest annual rate of 15% of 6 months?

 To calculate the annual interest rate equivalent to 15% for a period of 6 months, you can use the formula for calculating simple interest:

\[ I = P \times r \times t \]

Where:

- \( I \) = Interest earned

- \( P \) = Principal amount (initial amount of money)

- \( r \) = Interest rate per time period (in decimal form)

- \( t \) = Time period (in years)

Given:

- \( I = 15\% \) (annual interest rate)

- \( t = 6 \) months (which is \( \frac{1}{2} \) year)

Let's solve for \( r \):

\[ r = \frac{I}{P \times t} \]

\[ r = \frac{15\%}{P \times \frac{1}{2}} \]

\[ r = \frac{15\%}{\frac{1}{2}} \]

\[ r = 15\% \times 2 \]

\[ r = 0.15 \times 2 \]

\[ r = 0.30 \]

So, the interest rate per 6-month period is \( 0.30 \) (or 30% when expressed as a percentage). 

To convert it to an annual rate, you simply multiply it by the number of periods in a year:

\[ \text{Annual interest rate} = r \times \text{Number of periods in a year} \]

Since there are 2 periods of 6 months in a year:

\[ \text{Annual interest rate} = 0.30 \times 2 \]

\[ \text{Annual interest rate} = 0.60 \]

So, the annual interest rate equivalent to 15% for a period of 6 months is 60%.