Răspuns :
a+b+c=
b=3a
c=6a
c=b+30
/...../ a
/...../...../...../ b
/...../...../...../...../...../...../ c
/...../...../..../=30
/...../=30:3=10 lei prima zi (a0
b=3x10=30 lei a doua zi
c=6x10=60 lei a treia zi
10+30+60=100 lei a avut Ana
b=3a
c=6a
c=b+30
/...../ a
/...../...../...../ b
/...../...../...../...../...../...../ c
/...../...../..../=30
/...../=30:3=10 lei prima zi (a0
b=3x10=30 lei a doua zi
c=6x10=60 lei a treia zi
10+30+60=100 lei a avut Ana