The interest rate might be called the discount rate, opportunity cost of capital, compound rate as well as other terms we will discuss later. Often a firm or individualis interested in computing the interest rate associated with a financial transaction. The interest rate is often used as a measure of the project's risk when it is set by the market. Northern Air Lines is financing a new plane with a loan of company paying? $100,000 to be repaid in 5 annual end-of-year installments of $30,000. What annual interest rate is the Write your answer as a decimal