Question

Irina, radu si marius au impreuna 750 de timbre.Irina are cu 30 de timbre mai multe decat Radu,iar Marius de 4ori mai multe decat Radu Cate timbre are fiecare?

Answer 1

a+b+c=750 a=b+30 c=bx4 b+30+b+bx4=750 6b+30=750 6b=750-30 6b=720 b=720/6 b=120 a=120+30 a=150 c=120x4 c=480 150+120+480=750

Answer 2

Radu-r     

Marius-m
Irina-I

I+r+m=750 timbre 

I= 30+r

m=4 x r

I+r+m=750

(30+r)+r+(4 x r)=750         

30+r+r+4r=750

6r=750-30

6r=720

r=720: 6

r= 120 

I =30+120=150

m=120x4=480       R: Irina= 150 timbre

                                  Marius=480 timbre

                                   Radu= 120 timbre