IMO Shortlist 1968 problem 1
Dodao/la:
arhiva2. travnja 2012. Two ships sail on the sea with constant speeds and fixed directions. It is known that at
![9:00](/media/m/6/0/2/602a438aad1b82b95a303ad48db5cb45.png)
the distance between them was
![20](/media/m/1/1/e/11e1c5de3460c5571469b3ff0f222b7e.png)
miles; at
![9:35](/media/m/3/a/d/3ad7b9fd3396a5b16bf310f66ebec1aa.png)
,
![15](/media/m/8/f/3/8f3c9ff2c5f5085be88380fc85a87f7d.png)
miles; and at
![9:55](/media/m/9/d/8/9d8949d3789220cdf89a808bb6ad4ebf.png)
,
![13](/media/m/a/f/0/af007727d79ff468853d32d8393cc8de.png)
miles. At what moment were the ships the smallest distance from each other, and what was that distance ?
%V0
Two ships sail on the sea with constant speeds and fixed directions. It is known that at $9:00$ the distance between them was $20$ miles; at $9:35$, $15$ miles; and at $9:55$, $13$ miles. At what moment were the ships the smallest distance from each other, and what was that distance ?
Izvor: Međunarodna matematička olimpijada, shortlist 1968