What annual rate of interest was earned if a 15,000 investment for five months earned 546.88 in interest? (Do not round intermediate calculations and round your final answer to 2 decimal places.) Interest rate % per annum

## Step 1: Convert time to years<br />### The investment is for five months, which is $\frac{5}{12}$ of a year.<br /><br />## Step 2: Calculate the annual interest rate<br />### We are given $p = \$15,000$, $t = \frac{5}{12}$ years, and $i = \$546.88$. We use the formula $i = prt$ and solve for $r$: $r = \frac{i}{pt} = \frac{546.88}{15000 \cdot \frac{5}{12}} = \frac{546.88}{6250} = 0.0875008$. Multiply by 100 to express as a percentage: $0.0875008 \times 100 = 8.75008\%$. Rounding to two decimal places gives $8.75\%$.