Réponse :
Explications étape par étape
1/a 12 mn = 12.60=720s
9mn48s = 9.60+48 = 588s
3h29 = 3.60.60 + 29.60 = 12540s
2h7mn9s = 2.3600 + 7.60+9 = 7629s
b/ 6h = 6.60 =360mn
1h15 = 75mn
5h48 = 5.60+48 = 348mn
1j23h17mn = 24.60+23.60+17 = 2837mn
c/ 1896/60 = 31,6
37193/60= 619,883
619/60 = 10,316
1896mn = 113760s
37193s = 10h19mn53s
d/ 3876s = 1h 4mn 36s
18178s = 5h2mn58s
88400 = 24h33mn20s
16198s = 4h29mn58s