21 hari- 400 jam +2/7 minggu=..jam

21 hari - 400 jam + 2/7 minggu = ....jam
1 hari = 24 jam
1 minggu = 7 hari

21 hari(24 jam/hari) - 400 jam + 2/7 minggu(7hari/minggu) = ...jam
504 jam - 400 jam + 2 hari(24 jam/hari) =....jam
104 jam + 48 jam = 152 jam

(21x24 jam) - 400 jam -(2/7x168 jam)
= 504 jam - 400 jam - 48 jam
= 56 jam.
ket:
1 hari = 24 jm
1 minggu = 7 hari (7x24 jm = 168 jam