Problem 5.2. Alina, Bohdan, Vika, and Grisha came to the physical education lesson in shorts and T-shirts, and each of these items of clothing was either blue or red. Alina and Bohdan had red T-shirts, and their shorts were of different colors. Vika and Grisha had T-shirts of different colors, and their shorts were blue. It is also known that the girls had T-shirts of different colors, and their shorts were also different. What did each of the children wear?
Answer: Alina - red T-shirt and red shorts, Bogdan - red T-shirt and blue shorts, Vika - blue T-shirt and blue shorts, Grisha - red T-shirt and blue shorts.

Solution. Alina and Vika have different T-shirts according to the condition, so Vika has a blue T-shirt. Then Grisha has a red T-shirt. Therefore, the blue T-shirt is only for Vika.

Alina and Vika have different shorts according to the condition, so Alina has red shorts. Then Bogdan has blue shorts. Therefore, the red shorts are only for Alina.