prima zi: a doua zi=2 rest 13=> prima zi=2× a doua zi+13
prima zi+ a doua zi=124
a doua zi [..............]
prima zi [..............][...........][....+13...] acolada 124
2x+x+13=124
3x=124-13
3x=111+3
x=37
daca prima zi=x=> prima zi=37 ei
daca a doua zi=2x+13=> a doua zi=2×37+13=87 lei