Assume that the current interest rate on a 1-year bond is 8 percent, the current rate on a 2-year bond is 10 percent, and the current rate on a 3-year bond is 12 percent. If the expectations theory of the term structure is correct, what is the 1-year interest rate expected during Year 3? (Base your answer on an arithmetic rather than geometric average.)

I know the answer is 16% but im confused and dont know how to figure that out.