Question

Ana si Bogdan au impreuna 7 mere. Ana si Călin au impreuna 8 mere. Calculati câte  mere are Ana daca cei trei copii au impreuna 12 mere.

Answer 1

a+b=7
a+c=8

a+b+c=12
7+c=12
c=12-7
c=5 mere are calin

8+b=12
b=12-8
b=4 mere are bogdan

a+5+4=12
a+9=12
a=12-9
a=3 mere are ana

Answer 2

A+B= 7
A+C=8
A+B+C =12
7+C=12 =>C=5
A+5=8 =>A=3