bonjour
a) béatrice = b
andré = b - 2
pauline = b - 2
killian = b + 1
julia = 2 b
b + b - 2 + b - 2 + b + 1 + 2 b = 6 b - 3
2/3 ( 6 b - 3 ) = b + 1 + 2 b
2/3 ( 6 b - 3 ) = 3 b + 1
12 b /3 - 6/3 = 3 b + 1
4 b - 2 = 3 b + 1
4 b - 3 b = 1 + 2
b = 3
Béatrice = 3
André et Pauline = 1 chacun
Killian = 4
Julia = 6