Question

Гарри Поттер пишет волшебными чернилами записку. Он пишет 45 букв в минуту, причем каждую минуту исчезают 38 букв. В записке 135 букв. Сколько букв будет видно когда он закончит писать?

Answer 1

45-38=7б- столько букв остаются написанными  за 1 мин

135/45=3мин- потратил на написание записки

7*3=21б- будет видно букв

 

 

 

 

 

Answer 2

45-38=7 букв в минуту появляется

135:45=3 минуты писал записку

7*3=21 буква будет видна, когда закончит писать

Answer 3

Calculation of Visible Letters

To calculate the number of letters that will be visible when Harry Potter finishes writing, we need to consider the rate at which he writes and the rate at which the letters disappear.

According to the given information: - Harry writes 45 letters per minute. - Every minute, 38 letters disappear. - The note he is writing contains 135 letters.

To determine the number of visible letters, we can subtract the number of disappearing letters from the total number of letters written.

Let's calculate it step by step:

1. Calculate the number of disappearing letters: - Harry writes 45 letters per minute. - Every minute, 38 letters disappear. - So, the number of disappearing letters per minute is 38.

2. Calculate the number of visible letters per minute: - Harry writes 45 letters per minute. - Subtract the number of disappearing letters (38) from the number of letters written (45). - So, the number of visible letters per minute is 45 - 38 = 7.

3. Calculate the total number of visible letters: - Multiply the number of visible letters per minute (7) by the total number of minutes it takes to write the note. - The note contains 135 letters. - Divide the total number of letters (135) by the number of visible letters per minute (7) to find the total number of minutes. - So, the total number of minutes it takes to write the note is 135 / 7 = 19.2857 (rounded to 4 decimal places).

4. Calculate the number of visible letters when Harry finishes writing: - Multiply the number of visible letters per minute (7) by the total number of minutes it takes to write the note (19.2857). - Round the result to the nearest whole number. - So, the number of visible letters when Harry finishes writing is approximately 135 - 19 = 116.

Therefore, when Harry Potter finishes writing the note, approximately 116 letters will be visible.