Question

Crina si Radu au in total 234 de timbre . Radu are de 2 ori mai multe timbre decat Crina. Cate timbre are fiecare?

Answer 1

c+r=234
r=2c
c+2c=234
3c=234
c=234:3=78 timbre are Crina
r=2x78=156 timbre are Radu

Answer 2

c+r=234
r=2c
c+2c=234
3c=234
c=78
78+r=234
r=234-78
r=156
Raspuns:Crina=78
                Radu=156
Proba:156+78=234