Question

Trei copii au impreuna 216 timbre . Cate timbre are fiecare daca primul are de trei ori mai multe decat ceilalti doi la un loc, iar al treilea are cu 20 mai multe decat al doilea?

Answer 1

a+b+c=216[timbre]
⇒a=3[b+c];
⇒c=b+20;
⇒a=3[b+b+20]
⇒3b+3b+60+b+b+20=216[timbre]
⇒8b=216-[60+20]
⇒8b=216-80
⇒8b=136
⇒b=17;[timbre-al doilea copil];
⇒c=17+20
⇒c=37[timbre-al treilea copil];
⇒a=3[17+37]
⇒a=3·54
⇒a=162[timbre-primul copil];

Answer 2

a+b+c=216
a=3(b+c)=>a=3b+3c=>a=3b+3b+60=>a=6b+60
c=b+20
6b+60+b+b+20=216
8b=216-80
b=136:8
b=17 timbre are al2lea copil
c=17+20=37 timbre are al3lea copil
a=6x17+60=162 timbre are primul copil