50.)
f- fanel
m- Mirela
p- Pavel
f+m+p= 446
m= f+87
p= m+f
p= f+87+f
f+f+87+f+87+f= 446
4f+174= 446
4f= 446-174
4f= 272
f= 272/4
f= 68
m= f+87
m= 68+87
m= 155
p= m+f
p= 155+68
p= 223
verificare:
68+155+223= 446
446= 446, adevărat
51.)
a-b= 3348
a= 7b
7b-b= 3348
6b= 3348
b= 3348/6
b= 558
a= 7b= 7•558= 3906
verificare:
3906-558= 3348
3348= 3348, adevărat