Răspuns :
1h=60 min
15 min=1/4h
30 min=1/2h
notam x-fractia
x*60=15
x=15/60=>x=1/4
x*60=30
x=30/60=>x=1/2
15 min=1/4h
30 min=1/2h
notam x-fractia
x*60=15
x=15/60=>x=1/4
x*60=30
x=30/60=>x=1/2