Question

aflati nr.a,b,c:a+b+c=100 a+b=50 b+c=70

Answer 1

$a+b=50 \\ b+c=70 \\ a+b+c=100 \\ 50+c=100 \\ c=100-50 \\ \boxed{c=50} \\ b+50=70 \\ b=70-50 \\ \boxed{b=20} \\ a+20=50 \\ a=50-20 \\ \boxed{a=30}$