Question

7 друзей дежурят по очереди всю неделю.Каждый дежурит по одному разу. Имена дежурных:Андрей,борис,дима,григорий,евгений,сергей и федор. Кто в какой день дежурит если; 1.Андрей дежурит на следующий день после Сергея. 2.Борис дежурит на 2 дня раньше,чем Григорий. 3.Дима дежурит через 2 дня после, того дня , который предшевствует дежурству Евгения. 4.День дежурства Федора приходится на четверг,и находится посередине между днями дежурства Бориса и Сергея. Решите плиз!!!Помогите дам 25 баллов!

Answer 1

Мое предположение: понедельник - Сергей, вторник - Андрей, среда - Евгений, четверг - Федор, пятница - Григорий, суббота - Дима, воскресенье - Борис.

Answer 2

Кароче смотри, в понедельник дежурит Евгений. Во вторник Борис. В среду Дмитрий. В четверг Федор. В пятницу Григорий. В субботу Сергей. В воскресенье Андрей. По всем пунктам подходит)

Answer 3

Problem Analysis

We have 7 friends who take turns on duty throughout the week. Each friend takes a turn once. The names of the friends are: Андрей (Andrey), Борис (Boris), Дима (Dima), Григорий (Grigory), Евгений (Evgeny), Сергей (Sergey), and Федор (Fedor). We need to determine which friend is on duty on each day of the week based on the following conditions:

1. Andrey is on duty the day after Sergey. 2. Boris is on duty 2 days before Grigory. 3. Dima is on duty 2 days after the day preceding Evgeny's duty. 4. Fedor's duty day is on Thursday and is in the middle of Boris and Sergey's duty days.

Let's solve this step by step.

Solution

To solve this problem, we will create a table with the days of the week and the friends' names. We will start with an empty table and fill in the information based on the given conditions.

| Day | Friend | |-----------|-----------| | Monday | | | Tuesday | | | Wednesday | | | Thursday | | | Friday | | | Saturday | | | Sunday | |

1. Andrey is on duty the day after Sergey. - Based on this condition, we can determine that Sergey is on duty on Monday. Andrey will be on duty the day after Sergey, which is Tuesday. - Updated table:

| Day | Friend | |-----------|-----------| | Monday | Sergey | | Tuesday | Andrey | | Wednesday | | | Thursday | | | Friday | | | Saturday | | | Sunday | |

2. Boris is on duty 2 days before Grigory. - Based on this condition, we can determine that Grigory is on duty on Friday. Boris will be on duty 2 days before Grigory, which is Wednesday. - Updated table:

| Day | Friend | |-----------|-----------| | Monday | Sergey | | Tuesday | Andrey | | Wednesday | Boris | | Thursday | | | Friday | Grigory | | Saturday | | | Sunday | |

3. Dima is on duty 2 days after the day preceding Evgeny's duty. - Based on this condition, we need to determine the day preceding Evgeny's duty. Since Evgeny is on duty on Sunday, the day preceding Sunday is Saturday. Dima will be on duty 2 days after Saturday, which is Monday. - Updated table:

| Day | Friend | |-----------|-----------| | Monday | Sergey | | Tuesday | Andrey | | Wednesday | Boris | | Thursday | Dima | | Friday | Grigory | | Saturday | | | Sunday | Evgeny |

4. Fedor's duty day is on Thursday and is in the middle of Boris and Sergey's duty days. - Based on this condition, we can determine that Boris is on duty on Tuesday and Sergey is on duty on Monday. Fedor's duty day is on Thursday, which is in the middle of Boris and Sergey's duty days. - Updated table:

| Day | Friend | |-----------|-----------| | Monday | Sergey | | Tuesday | Boris | | Wednesday | | | Thursday | Fedor | | Friday | Grigory | | Saturday | | | Sunday | Evgeny |

Now we have filled in the table with the names of the friends on their respective duty days.

Answer

Based on the given conditions, the friends are on duty on the following days:

- Monday: Sergey - Tuesday: Boris - Wednesday: Dima - Thursday: Fedor - Friday: Grigory - Saturday: Andrey - Sunday: Evgeny

Please let me know if you need any further assistance!