X = 2.5Y --> Y = X \ 2.5
X = Z + 24 --> Z = X - 24
X + Y + Z = 93
X + ( X \ 2.5) + ( X - 24) = 93
2.5X + X + 2.5*(X - 24) = 232.5
X*(2.5 + 1 + 2.5) = 232.5 + 60
6X = 292.5
X = 48.75 - отцу
Y = 48.75 \ 2.5 = 19.5 - сыну
Z = 48.75 - 24 = 24.75 - дочери