On January 1, 2020, Madge Airways issued $3,500,000 of par value bonds for $3,200,000. The bonds pay interest semiannually on January 1 and July 1. The contract rate of interest is 7% while the market rate of interest for similar bonds is 8%. The bond premium or discount is being amortized using the straight-line method at a rate of $15,000 every six months. The life of these bonds is: 15 years 10 years 30 years o 20 years