I----I30I a+30=suma antonio dupa ce a primit 30 lei
I----I30I----I30I----I30I----I30I 3a+120=suma maria dupa ce i-a dat 30 lei
I----I a=suma initiala antonio
I----I30I----I30I----I30I----I30I30I 4a+150=suma initiala maria
4a+150=9a
5a=150
a=30 lei antonio
9a=9x30=270 lei maria
22.
550x1/5=110 l
550-110=440 l
440 x1/8=55 l
440-55 l=385 l