Réponse :
bonjour
Guillaume = x
Bernard = x - 2
Sabine = x - 2 + 10 = x + 8
x + x - 2 + x + 8 = 30
3 x = 30 - 8 + 2
3 x = 24
x = 8
Guillaume = 8
Bernard = 6
Sabine = 16
