If $917 earned $45 in 9 months, what was the simple interest rate of the investment

Example 2. Simple interest on $5000 over 4 years is $1800, what is the interest rate? Example 3. If you borrow $1200 at a 5% annual interest rate, how long will it take for the total amount owed to reach $1300? Example 4. Find the principal if the simple interest in 14 days at 25% per annum is 100.