Problem 4.4. Four girls: Katya, Olya, Liza, and Rita, stood in a circle in some order. They were wearing dresses of different colors: pink, green, yellow, and blue. It is known that:

- Katya was not wearing a pink or blue dress;
- the girl in the green dress is standing between Liza and the girl in the yellow dress;
- Rita is not in the green or blue dress;
- Olya is standing between Rita and the girl in the pink dress.

Who is wearing what
Answer: Katya is wearing a green dress, Olya - a blue one, Liza - a pink one, Rita - a yellow one. Solution. From the first and fourth statements, it follows that Katya, Olya, and Rita are not wearing pink dresses. Therefore, Liza is in the pink dress.

From the third statement, it follows that Rita is not wearing a green or blue dress. But she is also not in a pink one. Therefore, she is in a yellow dress.

From the first statement, it follows that Katya is not wearing a pink or blue dress. But she is also not in a yellow one. Therefore, she is in a green dress.

Accordingly, Olya is wearing the remaining blue dress.

It is also worth noting that if the girls stand in a circle in the order Rita-Olya-Liza-Katya, all the statements in the problem about who stands between whom will be true.