"" . , , .
"" "" (, ). , , , .
12 + 1 + 2 . .
15 . (1 + 12 + 2 . .) , .
, - .
= 12 . .
10 + 1 + 2 . .
13 . (10 + 1 + 2 . .) , .
= 10 .
, , . " " 70% 30% .
3 2 (3 2 )