Question

Когда четверых ребят спросили, сколько из них вчера ходили на каток, Саша ответила, что никто, Коля - что один человек, Тоня - что два, а Женя - что три. Известно, что правду сказали только те, кто ходил на каток. Сколько ребят ходили вчера на каток?

Answer 1

Известно, что правду сказали лишь те, кто был на катке. Если бы ребят было на катке двое или трое, то оба бы и ответили честно - одинаково. Так же было бы, если бы никто не пошел - все бы врали. Но по условию задачи кто-то вчера был на катке. Значит, на катке был и сказал правду один человек - Коля.

Answer 2

Problem Analysis

We are given a scenario where four children are asked how many of them went ice skating yesterday. Sasha says that nobody went, Kolya says that one person went, Tonya says that two people went, and Zhenya says that three people went. We are also told that only those who went ice skating told the truth. We need to determine how many children went ice skating yesterday.

Solution

To solve this problem, we need to analyze the statements made by each child and find the number of children who went ice skating.

Let's consider each child's statement:

- Sasha says that nobody went. This means that Sasha did not go ice skating. So, we can conclude that Sasha is telling the truth.

- Kolya says that one person went. If Kolya is telling the truth, then only one person went ice skating. However, if Kolya is lying, then more than one person went ice skating. Since we know that only those who went ice skating told the truth, we can conclude that Kolya is lying.

- Tonya says that two people went. If Tonya is telling the truth, then two people went ice skating. However, if Tonya is lying, then either one or three people went ice skating. Since we know that only those who went ice skating told the truth, we can conclude that Tonya is lying.

- Zhenya says that three people went. If Zhenya is telling the truth, then three people went ice skating. However, if Zhenya is lying, then either two or four people went ice skating. Since we know that only those who went ice skating told the truth, we can conclude that Zhenya is telling the truth.

Based on the analysis above, we can conclude that Sasha and Zhenya are telling the truth, while Kolya and Tonya are lying. Therefore, the number of children who went ice skating yesterday is three.

Answer

Three children went ice skating yesterday.