a=|---| a ; b = a+18 ; c = b+13 = a+18+13 = a+31
b=|---|+18 a+b+c = a + a+18 + a+31 = 154
c=|---|+18+13 3a = 154-31-18
a+b+c = 3*|---|+18+18+13=154 a = 105:3
↓ a = 35
3*|---| = 154-(18+18+13)
|---| = 105:3=35
deci: a=35 ; b= 35+18=53 si c=35+18+13=66