On the island of Castor, there are 40 chess players. A quarter of the island's chess players have never lost to an AI. How many people on the island have lost to a computer, at least once?
Chess players that have never lost to an AI is 40/4 = <<40/4=10>>10 people.
Chess players that have lost to an AI is 40-10 = <<40-10=30>>30 people.
#### 30