Kanel-Belov A.Y.

A mushroom is called bad if it contains no less than 10 worms. In the basket, there are 90 bad and 10 good mushrooms. Can all the mushrooms become good after some worms crawl from the bad mushrooms to the good ones?
Let there be exactly 10 worms in each bad mushroom, and no worms in good mushrooms. Further, let one worm from each bad mushroom crawl into the good ones, with 9 worms crawling into each good mushroom. As a result, there will be 9 worms in each mushroom, and all mushrooms will be good.

## Answer

They can.