Răspuns :
420=7ore 540=9ore 1200=20ore 7200=120minute(doua ore) 21600=360 minute(sase ore)
420 min = 7 h
540 min = 9 h
1200 min = 20 h
7200 s = 120 min = 2 h
21600 s = 360 min = 6 h
540 min = 9 h
1200 min = 20 h
7200 s = 120 min = 2 h
21600 s = 360 min = 6 h