On January 1 of Year 1, Congo Express Airways issued $4,200,000 of 7%, bonds that pay interest semiannually on January 1 and July 1. The bond issue -price is $3,660,000 and the market rate of interest for similar bonds is 9%. The bond premium or discount is being amortized using the straight-line method at a rate of $13,500 every six months. The life of these bonds is: Multiple Choice 40 years 20 years. 15 years 27 years 31 years