Question

Десять ветряных мельниц смололи 200 четвертей ржи в 12 дней, работая в день по 14 часов. По сколько часов в день должны работать восемь таких же мельниц, чтобы в 21 день смолоть 300 четвертей ржи?

Answer 1

Х-кол-во часов для 8 мельниц
Составим уравнение 
у-производительность мельницы за 1 час
У=200/10*12*14=20/168=0.11905
Составим уравнение для 8 мельниц
х=300/8*21*20/168=15 ч
Ответ: по 15 часов

Answer 2

Problem Analysis

We are given that ten windmills ground 200 quarters of rye in 12 days, working 14 hours per day. We need to determine how many hours per day eight windmills should work in order to grind 300 quarters of rye in 21 days.

Solution

To solve this problem, we can set up a proportion based on the given information. Let's denote the number of hours per day that the eight windmills should work as x.

According to the given information: - Ten windmills ground 200 quarters of rye in 12 days, working 14 hours per day. - We need to find the number of hours per day that eight windmills should work to grind 300 quarters of rye in 21 days.

We can set up the following proportion:

10 windmills : 8 windmills = 200 quarters : 300 quarters

12 days : 21 days = 14 hours : x hours

To solve this proportion, we can cross-multiply and solve for x.

10 * 300 * 14 = 8 * 200 * x

Simplifying the equation:

42000 = 1600x

Dividing both sides by 1600:

x = 26.25

Therefore, the eight windmills should work approximately 26.25 hours per day to grind 300 quarters of rye in 21 days.

Answer

The eight windmills should work approximately 26.25 hours per day to grind 300 quarters of rye in 21 days.