1)
Notam cartea=c;ghiozdanul=g;penarul=p
c=3p
g=2p+c=2p+3p=5p
g-p=32
5p-p=32
4p=32
p=32:4=8 lei costa 1 penar
c=3p=3x8=24 lei costa cartea
g=5p=5x8=40 lei costa ghiozdanul
24+8+40=72 lei a platit mama
2)a |-----|-----|-----|-----|
b |-----|-----|-----|
c |-----|
c=984:8=123
b=123x3=369
a=123x4=492
123+369+492=984