a+b+c=190
a=100
b=2c
100+b+c=190
100+2c+c=190
3c=190-100
3c=90
c=90:3
c=30
b=2x30=60
V: 100+60+30=190
R: a doua zi 60 de cantece
a treia zi 30 cantece
..................................................................
l zi =100
ll zi /.../.../
lll zi /.../ total 190
/.../.../.../=190-100=90
/.../=90:3=30 ( a treia zi)
/.../.../=30x2=60 ( a doua zi)