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All-Russian Olympiad
1966 All Russian Mathematical Olympiad
076
076
Part of
1966 All Russian Mathematical Olympiad
Problems
(1)
ASU 076 All Russian MO 1966 shortest path on cross-lined paper
Source:
6/19/2019
A rectangle
A
B
C
D
ABCD
A
BC
D
is drawn on the cross-lined paper with its sides laying on the lines, and
∣
A
D
∣
|AD|
∣
A
D
∣
is
k
k
k
times more than
∣
A
B
∣
|AB|
∣
A
B
∣
(
k
k
k
is an integer). All the shortest paths from
A
A
A
to
C
C
C
coming along the lines are considered. Prove that the number of those with the first link on
[
A
D
]
[AD]
[
A
D
]
is
k
k
k
times more then of those with the first link on
[
A
B
]
[AB]
[
A
B
]
.
algebra