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Problems
Contests
National and Regional Contests
Italy Contests
ITAMO
1995 ITAMO
2
2
Part of
1995 ITAMO
Problems
(1)
20 students with integer scores in maths
Source: 1995 ITAMO p2
1/28/2020
No two of
20
20
20
students in a class have the same scores on both written and oral examinations in mathematics. We say that student
A
A
A
is better than
B
B
B
if his two scores are greater than or equal to the corresponding scores of
B
B
B
. The scores are integers between
1
1
1
and
10
10
10
. (a) Show that there exist three students
A
,
B
,
C
A,B,C
A
,
B
,
C
such that
A
A
A
is better than
B
B
B
and
B
B
B
is better than
C
C
C
. (b) Would the same be true for a class of
19
19
19
students?
combinatorics