MathDB
Problems
Contests
National and Regional Contests
Kyrgyzstan Contests
Kyrgyzstan National Olympiad
2016 Kyrgyzstan National Olympiad
2
2
Part of
2016 Kyrgyzstan National Olympiad
Problems
(1)
nice combinatorics problem
Source: KGZ national 2016 2-problem
5/10/2016
The number
N
N
N
consists only
2
′
s
2's
2
′
s
and
1
′
s
1's
1
′
s
in its decimal representation.We know that,after deleting digits from N,we can get any number consisting
9999
9999
9999
-
1
′
s
1's
1
′
s
and
o
n
e
one
o
n
e
-
2
′
s
2's
2
′
s
in its decimal representation.Find the least number of digits in the decimal representation of N
combinatorics