Puzzle n°33 (**) - The Automatic Feeders Homepage  

In a cat pension, cats were living in large enclosures with automatic feeders.
These feeders were used to distribute a fresh amount of croquettes every day.
They were all the same : a bowl with plenty of croquettes available at first
(with the same amount of croquettes for each feeder),
and, every day, the feeder dropped an additional amount of croquettes in the bowl,
(every day the same amount).

As these feeders were new for the keepers of the pension,
they didn't quite know if the starting quantities and daily amounts were rightly calibrated.
After having installed brand new feeders in two enclosures, they noticed that :

  • in the first enclosure where 10 cats lived, and where they had put 10 feeders,
    the feeder bowls never were empty until the 10th day,
    where the cats ate all what was left in the bowls.
  • in the second enclosure where 15 cats lived, and where they had put 22 feeders,
    the feeder bowls became empty on the 44th day.
Lunch time

There was a third enclosure in the pension, with 20 cats.
The keepers put 17 feeders in this enclosure, all with the same initial quantity of croquettes in the bowl
and the same amount added daily for each of them.
They were wondering how long would it take for the bowls to be first empty...

Would you be able to tell them ?

NB : all cats in the pension are supposed to eat the same amount every day...

... I'm giving up ...


© Marie-Bernadette Pautet, 2005-2019
Last page update: 10.9.2008