Question

Одна швея может выполнить работу за 4 часа, а другая - за 5 часов. Какую часть работы выполнят они, работая вместе, за 2 часа? Какая часть работы останется невыполненной?

Answer 1

В задачах на работу обычно всю работу принимают за 1.
1) 1:4=1/4=0,25 (часть работы) - 1-я швея за 1 ч
2) 1:5=1/5=0,2 (часть работы) - 2-я швея за 1 ч
3) 0,25+0,2=0,45 (часть работы) - 1-я и 2-я за 1 ч вместе
4) 0,45·2=0,9 (работы) - вместе за 2 ч
5) 1-0,9=0,1 (работы) - останется

Answer 2

Calculation of Work Completed and Work Remaining

To determine the portion of work completed and the portion of work remaining when two seamstresses work together for 2 hours, we need to consider the individual rates at which they complete the work.

Let's assume that the first seamstress can complete the work in 4 hours, while the second seamstress can complete the same work in 5 hours.

To calculate the portion of work completed by each seamstress, we can use the formula:

Portion of work completed = (Time worked / Time required to complete the work)

For the first seamstress: - Time worked = 2 hours - Time required to complete the work = 4 hours

Portion of work completed by the first seamstress = (2 / 4) = 0.5

For the second seamstress: - Time worked = 2 hours - Time required to complete the work = 5 hours

Portion of work completed by the second seamstress = (2 / 5) = 0.4

Therefore, when working together for 2 hours, the first seamstress completes 50% of the work, while the second seamstress completes 40% of the work.

To calculate the portion of work remaining, we subtract the portion of work completed from 1 (100%).

Portion of work remaining = 1 - (Portion of work completed)

For the first seamstress: Portion of work remaining for the first seamstress = 1 - 0.5 = 0.5 (50%)

For the second seamstress: Portion of work remaining for the second seamstress = 1 - 0.4 = 0.6 (60%)

Therefore, when working together for 2 hours, 50% of the work remains incomplete for the first seamstress, while 60% of the work remains incomplete for the second seamstress.

Please note that these calculations assume that the work is evenly distributed between the two seamstresses and that their rates of work remain constant throughout the task.