a)1/4 h × 3600 s/h =900 s
3/2 min=3/2×60 s/min= 90 s
b)1/2 h ×60 min/h=30 min
1/3 h ×60 min/h=20 min
1/12 h ×60 min/h=5 min
2/5 h ×60 min/h=24 min
5/6 h ×60 min/h=50 min
3/20 h ×60 min/h=9 min
c)3600 minute : 60 min/h= 60 ore
483840minute : 60 min/h= 8064 ore
5 zile ×24 h=120 h
1 saptamina ×7zile/saptamana× 24 h/zi=168 h