Question

Мама может вымыть посуда за 20 мин. А доч за 30 мин.О тветьте на следущие вопросы: ! Какую часть раб.может вып.мама за 1 мин? Какаю часть раб. может выполнить дочь за 1 мин.? Какую часть работы могут выполнить за 1 минуту мамам и дочь вместе ? За сколько минут вымоют посуду мама и дочь работая вместе?

Answer 1

за 1 минуту мама помоет 0,2 %  

за 1 минуту дочь помоет 0,3 %

за 1 минуту мама и дочь помоют 0,5%

работая вместе мама и дочь помоют посуду за 25 минут , т.к   20+30/2=25

 

Answer 2

Calculation of Work Efficiency

To answer your questions, let's calculate the work efficiency of both the mother and the daughter.

The mother can wash the dishes in 20 minutes, which means she can complete 1/20th of the work in 1 minute.

The daughter, on the other hand, takes 30 minutes to wash the dishes, so she can complete 1/30th of the work in 1 minute.

Combined Work Efficiency

To determine the combined work efficiency of the mother and daughter working together, we can add up their individual work efficiencies.

The combined work efficiency is the sum of the work efficiencies of the mother and daughter, which is 1/20 + 1/30.

To simplify the calculation, we can find the least common multiple (LCM) of 20 and 30, which is 60.

So, the combined work efficiency is 3/60 + 2/60 = 5/60.

Therefore, the mother and daughter together can complete 5/60th of the work in 1 minute.

Time to Wash the Dishes Together

To calculate the time it takes for the mother and daughter to wash the dishes together, we can divide the total work (1) by their combined work efficiency (5/60).

So, the time it takes for the mother and daughter to wash the dishes together is 60/5 = 12 minutes.

Therefore, the mother and daughter working together can wash the dishes in 12 minutes.

Please note that the calculations provided above are based on the given information and assumptions.