Răspuns :
a+b+c=435
a+b=251 =>a+b+b+c=570 =>435+b=570 =>b=135
b+c=319 a+135=251 =>a=116
=>c+135=319 =>c=184
a+b=251 =>a+b+b+c=570 =>435+b=570 =>b=135
b+c=319 a+135=251 =>a=116
=>c+135=319 =>c=184
a+b+c=435
a+b=251 => a=251-b
b+c=319 => c=319-b
251-b+b+319-b=435
570-b=435
=> b=135 elevi in a 2-a scoala
a=251-135
=> a=116 elevi in prima scoala
c=319-135
=> c=184 elevi in a III-a scoala
a:|___|-116
b:|____|-135
c:|________|-184
a+b=251 => a=251-b
b+c=319 => c=319-b
251-b+b+319-b=435
570-b=435
=> b=135 elevi in a 2-a scoala
a=251-135
=> a=116 elevi in prima scoala
c=319-135
=> c=184 elevi in a III-a scoala
a:|___|-116
b:|____|-135
c:|________|-184