Question

Когда Петя учился во втором классе, скорость его чтения была 45 слов/мин. В четвёртом классе скорость чтения Пети - 135 слов/мин. За сколько часов смог бы четвероклассник Петя прочитать книгу, которую во втором классе он читал в течение 4 ч? Пожалуйста по действиям с объяснениями.

Answer 1

4 часа = 4*60 минут = 240 минут
1)45*240 = 10 800 слов в книге
2) 10 800 : 135 = 80 минут потребуется
Ответ:80 минут или 1 час и 20 минут потребуется Пете для прочтения книги.

Answer 2

Calculation of Reading Speed Increase

To calculate the time it would take for fourth-grader Petya to read a book that he read in second grade for 4 hours, we need to determine the increase in his reading speed from second grade to fourth grade.

Petya's reading speed in second grade was 45 words per minute In fourth grade, his reading speed increased to 135 words per minute.

To find the increase in reading speed, we subtract the reading speed in second grade from the reading speed in fourth grade:

Increase in reading speed = Reading speed in fourth grade - Reading speed in second grade Increase in reading speed = 135 words per minute - 45 words per minute Increase in reading speed = 90 words per minute

Now, we can calculate the time it would take for Petya to read the book in fourth grade:

Time = Number of words / Reading speed Time = 4 hours x 60 minutes / (45 words per minute + 90 words per minute) Time = 240 minutes / 135 words per minute Time ≈ 1.78 minutes

Therefore, it would take Petya, a fourth-grader, approximately 1.78 minutes to read the book that he read in second grade for 4 hours.

Please note that this calculation assumes a constant reading speed throughout the entire duration of reading and does not take into account factors such as comprehension or breaks.