At the space carnival, visitors can try two special attractions: the Zero-Gravity Room or the Laser Maze. By the end of the day:
\(100\) visitors have tried at least one of the two attractions,
\(50\) visitors tried the Laser Maze,
\(20\) visitors tried both attractions.
How many visitors tried only the Zero-Gravity Room?
We write all \(26\) different letters of the English alphabet in a line, using each letter exactly once.
How many such arrangements do not contain any of the strings
fish, rat, or bird?