1)
Forfait n°1
0.90 × 10 = 9€
Forfait n°2
24 + 0.50 × 10 = 29€
2)
Plus petit commun multiple
0.90 ÷ 2 = 0.45
0.45 ÷ 3 = 0.15
0.15 ÷ 3 = 0.05
0.05 ÷ 5 = 0,01
0.01 ÷ 0,01 = 1
0.90 = 2×3²×5×0.01
0.50 ÷ 2 = 0.25
0.25 ÷ 5 = 0.05
0.05 ÷ 5 = 0.01
0.01 ÷ 0.01 = 1
0.50 = 2×5²×0.01
3²×5² = 225 musiques
225×0.90 = 202.5€
24 + 225×0.50 = 136.5€