Question

Одна поливочная машина может полить всю улицу за 15 минут,а другая за 12 минут.Какую часть улицы польют обе машины за 1 минуту? за 3 минуты?ПОМОГИТЕ НУЖНО ДО 22.04.2013Г!!!

Answer 1

принимаем всю работу за 1,тогда

1)1:15=1/15 польёт первая машина за 1 мин

2)1:12=1/12 польёт вторая машина за 1 мин

3)1/15+1/12=3/20 польют обе машины за 1 мин

4)3*3/20=9/20 польют обе машины за 3 мин

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Answer 2

Первая машина за 1 минуту польет 1/15 улицы, вторая -- 1/12 улицы.

 

Вместе за 1 минуту они польют: 1/15+1/12=4/60+5/60=9/60=3/20=15/100=0,15 улицы

Answer 3

Calculation of the Proportion of the Street Watered by Both Machines

To determine the proportion of the street that both machines can water in a given time, we need to calculate the rate at which each machine waters the street.

Let's assume that the length of the street is 1 unit (it could be any unit of measurement, such as meters or kilometers).

Machine A can water the entire street in 15 minutes, which means it can water 1/15 of the street in 1 minute.

Machine B can water the entire street in 12 minutes, which means it can water 1/12 of the street in 1 minute.

To find the proportion of the street that both machines can water in 1 minute, we need to add their individual rates:

1/15 + 1/12 = 9/180 + 15/180 = 24/180 = 2/15

Therefore, both machines can water 2/15 of the street in 1 minute.

Calculation for 3 Minutes

To find the proportion of the street that both machines can water in 3 minutes, we multiply the rate calculated above by 3:

3 * (2/15) = 6/15 = 2/5

Therefore, both machines can water 2/5 of the street in 3 minutes.

Please note that the calculations above assume that the machines work at a constant rate and that there are no other factors that may affect their efficiency.

I hope this helps! Let me know if you have any further questions.