Need help understanding and intuition behind this problem and how to solve:

EXERCISE #7: A 5-year 5% annual coupon bond yields 4%. Compute the Macaulay duration of the bond. Do this by filling in the following table. (1) (2) (3i (4) (5) Time until Payment Discounted Weight: Column (1) Payment Payment at 4% (3)/Sum(3) x (Years) Column (4) 1 50 2 50 3 50 4 50 5 1050 Column Sum: 1.0000 From bottom (sum) of Col 3, Price = $ ................................... From bottom (sum) of Col 5, Duration = ....................... years