Please show all the math in a way that easy to understand!

You sell a $1,000-par zero-coupon bond that has seven years of remaining maturity. Rates are 7%. You plan on buying the bond back in one year and believe that the interest rate next year will have the following probability distribution: [Probability Interest Rate Next Year (%)); [0.156.0]; (0.25 6.25); [0.4 | 6.5]; [0.15| 6.75); (0.05 | 7.0]: Your return on this transaction is %? (Round to the nearest %)