Question

Să se afle trei numere stiind ca mediile aritmetice a doua câte doua numere sunt: 2,(3); 3,(1); respectiv 1,(5)

Answer 1

2,(3)=(23-2)/9=21/9
3,(1)=(31-3)/9=28/9
1,(5)=(15-1)/9=14/9
(a+b)/2=21/9   ⇒ a+b=42/9
(b+c)/2=28/9   ⇒ b+c=56/9
(c+a)/2=14/9   ⇒ c+a=28/9
a+b+b+c+c+a=42/9+56/9+28/9
2(a+b+c)=126/9
(a+b+c)=63/9
(a+b+c)=7
a=7-(b+c)=7-56/9=7/9
b=7-(a+c)=7-28/9=35/9
c=7-(a+b)=7-42/9=21/9=7/3