Broj oblika
zovemo ukrasnim ako je on aritmetička sredina brojeva
,
i
(pri čemu su
znamenke od 0 do 9). Koliko ima ukrasnih brojeva?
Number of form
is called decorative if it is an arithmetic mean of numbers
,
and
(where
are digits from 0 to 9). How many decorative numbers are there?
[lang=hr]
Broj oblika $0.abcabc...$ zovemo ukrasnim ako je on aritmetička sredina brojeva $0.aaaa...$, $0.bbbb...$ i $0.cccc...$ (pri čemu su $a, b, c$ znamenke od 0 do 9). Koliko ima ukrasnih brojeva?
[/lang]
[lang=en]
Number of form $0.abcabc...$ is called decorative if it is an arithmetic mean of numbers $0.aaaa...$, $0.bbbb...$ and $0.cccc...$ (where $a, b, c$ are digits from 0 to 9). How many decorative numbers are there?
[/lang]
