Problem #PRU-89945

Problems Methods Examples and counterexamples. Constructive proofs
 10–12  2.0

Problem

Five oaks are planted along two linear park alleys in such a way that there are three oaks along each alley, see picture. Where should we plant the sixth oak so that it will be possible to lay two more linear alleys, along each of which there would also be three oak trees growing?
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