Question

Marin , Radu si Andra au impreuna 89de surprize. Marin si Andra au 54 de surprize, iar Radu ai Andra 48 de surprize . Cate surprize au fiecare ?

Answer 1

m nr surprize Marin
r nr surprize Radu
a nr surprize Andra
m+r+a=89 (1)
m+a=54 (2)
r+a=48 (3)
din (1) si (2) r= 89-54, r=35 Radu are 35 surprize
din (1) si (3) m= 89-48, m=41 Marin are 41 surprize
Inlocuim in relatia (2) 41+a=54 a= 13 Andra are 13 surprize
Verificare 41+35+13=89

Answer 2

M+R+A=89
M+A=54
R+A=48
M+48=89
M=41
M+A=54
41+A=54
A=54-41=13
41+R+13=89
R=89-41-13=48-13
R=35