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Problems
Contests
National and Regional Contests
Moldova Contests
Moldova Team Selection Test
1997 Moldova Team Selection Test
12
12
Part of
1997 Moldova Team Selection Test
Problems
(1)
Let $A$ be a set of $n$ positive integers.
Source: Moldova TST 1997
8/8/2023
For every nonempty set of real numbers
S
S{}
S
denote
σ
(
S
)
\sigma(S)
σ
(
S
)
the sum of its elements. Let
A
A{}
A
be a set of
n
n{}
n
positive integers. Show that the set of all sums
σ
\sigma{}
σ
of all nonempty sets of
A
A{}
A
can be partitioned in
n
n{}
n
groups such that the ratio between the greatest number and the smallest number from each group is less than
2
2
2
.