B-suma de bani Bogdan
S-suma de bani Stefan
D-suma de bani Dragos
A-suma de bani Ana
B=5A
S=B-50=> S=5A-50
D=15 lei
S=D x 21
S=15 x 21
S= 315
S=5A-50=315
5A=50 + 315
5A=365
A=365 : 5
A=73
B=5 A
B= 5 x 73
B= 365
Bogdan are 365 de lei,Ana are 73 de lei,Stefan are 315 lei si Dragos are 15 lei .