Question

Швея за 12 минут обтачивает комплект белья ,а ученица за 27 минут.За сколько минут , работая вместе комплект постельного белья будет готов

Answer 1

Швея - 12 мин.
ученица - 27 мин.
вместе - ? мин.
1. 12 + 27 = 39 (мин.) сумма времени швеи и ученицы.
2. 39 : 2 = 19,5 (мин) уйдет на пошив комплекта, если будут работать двое.

Answer 2

Calculation of Sewing Time

To calculate the time it takes for the seamstress and the apprentice to complete a set of bed linen, we need to determine their individual sewing rates.

According to the information provided, the seamstress can complete a set of bed linen in 12 minutes, while the apprentice takes 27 minutes to complete the same task.

To find the time it takes for them to complete the set of bed linen when working together, we can use the concept of "work done per unit of time."

Let's denote the time it takes for them to complete the set of bed linen when working together as T.

The seamstress's sewing rate can be expressed as 1/12 of the set of bed linen per minute, while the apprentice's sewing rate is 1/27 of the set of bed linen per minute.

When they work together, their sewing rates are additive. Therefore, the combined sewing rate is 1/12 + 1/27 of the set of bed linen per minute.

To find the time it takes for them to complete the set of bed linen when working together, we can set up the following equation:

1/12 + 1/27 = 1/T

Solving this equation will give us the value of T, which represents the time it takes for them to complete the set of bed linen when working together.

Let's calculate the value of T:

1/12 + 1/27 = 1/T

To solve this equation, we can find a common denominator of 324:

(27 + 12) / 324 = 1/T
39 / 324 = 1/T

Cross-multiplying:

39T = 324
T = 324 / 39
T ≈ 8.31 minutes

Therefore, when working together, the seamstress and the apprentice will take approximately 8.31 minutes to complete the set of bed linen.

Please note that the calculated value is an approximation and may not be exact due to rounding.

Answer:

When working together, the seamstress and the apprentice will take approximately 8.31 minutes to complete the set of bed linen.