Question

Corina si Maria au impreuna 160 de abtibilduri, Maria si Irina au impreuna 134 de abtibilduri, iar Corina si Irina au impreuna 146 se abtibilduri. 

Cate abtibilduri are fiecare fetita?

Answer 1

C+M=160
M+I=134
C+I=146
 le adun
2C+2M+2I=160+134+146
2(C+M+i)=440
C+M+I=440:2=220
I=220-160=60
C=220-134= 86
M= 220-146=74

Answer 2

C=a,,,M=b,,I= c    a+b=160,,b+c=134,,a+c=146  (a+b)+(b+c)+(a+c)=160+134+146  2a+2b+2c=440  ,,2(a+b+c)=440  a+b+c=440:2=220      160+c=220,,c=220-160=60,, c=60  b+60=134  b=134-60=74  b=74    a+60=146  a=146-60=86  a=86