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National and Regional Contests
Indonesia Contests
Indonesia MO Shortlist
2015 Indonesia MO Shortlist
C7
C7
Part of
2015 Indonesia MO Shortlist
Problems
(1)
subset of {1,2, 3,... , 2014}, with 12 elements, with numbers of sum = 2015
Source: INAMO Shortlist 2015 C7
5/14/2019
Show that there is a subset of
A
A
A
from
{
1
,
2
,
3
,
.
.
.
,
2014
}
\{1,2, 3,... , 2014\}
{
1
,
2
,
3
,
...
,
2014
}
such that : (i)
∣
A
∣
=
12
|A| = 12
∣
A
∣
=
12
(ii) for each coloring number in
A
A
A
with red or white , we can always find some numbers colored in
A
A
A
whose sum is
2015
2015
2015
.
combinatorics
Sum
Subset