Răspuns :
[----]--13,02--] cartea [----] pixul 57-13,02=43,98 43,98:2=21,99 lei costa pixul 21,99+13,02=35,01 lei costa cartea
a-pixul
b-cartea
a+b=57
a=b-13,02
b-13,02+b=57
2b=57+13,02
2b=70,02
b=70,02:2=35,01lei carte
a=35,01-13,02=21,99 lei pix
b-cartea
a+b=57
a=b-13,02
b-13,02+b=57
2b=57+13,02
2b=70,02
b=70,02:2=35,01lei carte
a=35,01-13,02=21,99 lei pix