Réponse :
2h48min52sec+4h36min+15sec
on convertit en sec : 2*3600+48*60+52+4*3600+36*60+15=26 707sec
on convertit en h : 26707/3600=7,41..soit 7h
il reste en sec : 26707-3600*7=1507sec
on convertit en min : 1507/60=25,11666...min=25min
il reste en sec : 26 707-3600*7-25*60=7sec
2h48min52sec+4h36min+15sec=7h25min07sec
6) 4h48hd =4h28min48sec
4h48 =
4h+0,48h=
4h+(0,48*60)min=
4h+28,8min=
4h+28min+(0,8*60)sec=4h28min48sec
7)3h34min52sec= 12 892sec
3*3600+34*60+52=12 892sec
8)2h26min54sec= 2*3600+26*60+54=8814sec
8814*3=26 442sec = 7h20min42sec
26442/3600=7,345h = 7h
26442-7*3600=1242sec
on cherche les min 1242/60=20,7min soit 20min
on cherche les sec42-3600*7-20*60=42sec
resultat : 7h20min42sec
Explications étape par étape :
