0,(3)= 3/9=1/3
11. transpui in limbaj matematic a×2 = b×1/3 = k
a= k/2, b= k/1/3= k×3= 3k
stiind ca (a+b)/2= 6,8 => a+b= 6,8×2 => a+b= 13,6
k/2 + 3k = 13,6 amplifici pe 3k si pe 13,6 cu 2
k+ 6k= 27,2
7k= 27,2
k= 272/10 ×1/7
k= 272/70 = 136/35
a= 136/35/2= 136/35 ×1/2=> a= 68/35
b= 3×136/35 => b= 408/35
