Final answer:
To earn $35.75 interest at an annual interest rate of 3% for 180 days, the principal that must be invested is $2421.25.
Step-by-step explanation:
To calculate the principal amount that must be invested at an annual interest rate of 3% for 180 days to earn $35.75 interest, we can use the formula:
Principal = Interest / (Rate * Time)
Plugging in the given values, we get:
Principal = $35.75 / (0.03 * (180/365))
Principal = $35.75 / (0.03 * 0.493)
Principal = $35.75 / 0.01479
Principal = $2421.25
Therefore, the principal that must be invested is $2421.25.