bonsoir
billet enfant = x
billet adulte = x + 1.5
27 x + 15 ( x + 1.5) = 169.50
27 x + 15 x + 22.5 = 169.50
42 x = 169.50 - 22.5
42 x = 147
x = 3.5
enfant = 3.50 et adulte = 5 €
