Найдите сумму всех делителей числа 39.

39 /1 = 39 39/3 = 13 39/13 = 3 39/39=1

39 : 3 = 13 13 : 13 = 1 39 = 3 * 13 - простые множители сумма делителей числа 39 = 1 + 3 + 13 + 39 = 56 

Лера - 4

Ваня - 9

Ира - 11

Юля - 16.

Пошаговое объяснение:

Д-Девочка

И-Ира

В-Ваня

Л-Лера

Ю-Юля.

Так как 1 Д в дед сад ходит, ставим на 1 место Д.

Д.

И старше В, значит И правее В.

Д ???? В, И, ????

Сумма лет И и Л (x) делится на 5, это нам сейчас ничего не дает.

Будем работать методом исключения.

Если И старше В, то:

И - (Или 9 или 11 или 16.)

В- (Или 11 или 9)

Юля (Или 16 или 4)

Лера (4 или 16).

Допустим Лере 4 года, тогда Ире либо 11 либо 16. Юле 16, Ване 9, Ире 11.

Допустим Юле 4, Лере 16 Ире 11, Ване 9. Но тогда И+Л= 16+11=27 (Не делится на 5)

Тоесть, ответ таков:

Лера - 4

Ваня - 9

Ира - 11

Юля - 16.

Dear Helen,

How are the things going on? Did something new happen in your life? Having received your letter, I wanted to answer it immediately but I was working a lot during the last two weeks. So I was pressed for time and did not manage to carry out my intentions.

In my country spring has already set. It is quite warm and really sunny all days long. Being at work I always imagine myself strolling down some parks. I wish you could join me! It would be funny! Some days ago my friend advised me to read a very interesting book. I did it and I would like you to know this author. Are you ready to read good literature?

Tell me more about your work and free time. Are you satisfied with all this? What are your plans for this summer? Maybe we will be able to meet one day?

Truly yours,

Jessica