Question

Здравствуйте!Помогите решить 2 задачи по математике.За 4 класс. а)Мастер делает 120 деталей за 8 ч.Но когда он работает вместе с учеником,то это же количество деталей они успевают сделать за 5 ч.Сколько деталей в 1 ч делает ученик?(С краткой записью,и с действиями) б)На строительную площадку нужно перевезти 120 т песка.Одна машина может это сделать за 40 рейсов,другая -за 24 рейса.За сколько рейсов перевезут песок эти машины,работая вместе?(краткая запись,с действиями).Спасибо!

Answer 1

1)

Сам - 120 дет за 8 час

С учеником - 120 дет за 5 час

Ученик - ? в час

120/8=15 дет в час - делает мастер

120/5=24 дет в час - делает мастер и ученик

24-15 = 9 дет в час - делает ученик

Ответ. 9 деталей в час

2)

Всего 120 т

Первая - 40 рейсов

Вторая - 24 рейса

Перевезут вместе  - ? рейсов

120/40 = 3 т - перевозит за 1 рейс первая машина

120/24=5 т - перевозит за 1 рейс вторая машина

3+5 = 8 т - перевезут за 1 рейс обе машины

120/8= 15 рейсов - необходимо сделать машинам

Ответ. 15 рейсов

Answer 2

Task a) Finding the Number of Details Made by the Student per Hour

To find out how many details the student makes in 1 hour, we can use the information given about the master and the student working together.

The master makes 120 details in 8 hours, and when working with the student, they make the same amount of details in 5 hours. We can use this information to calculate the number of details the student makes in 1 hour.

Let's denote the number of details the student makes in 1 hour as x.

The master's rate can be expressed as 120 details / 8 hours = 15 details per hour.

When working with the student, their combined rate is 120 details / 5 hours = 24 details per hour.

Using this information, we can set up the equation: 15 (master's rate) + x (student's rate) = 24 (combined rate)

Solving for x, we get: x = 24 - 15 x = 9

So, the student makes 9 details in 1 hour.

Task b) Determining the Number of Trips Required by Each Truck

In this task, we need to determine how many trips each truck will take to transport 120 tons of sand.

One truck can transport the sand in 40 trips, and the other truck can do it in 24 trips. We can use this information to calculate the number of trips required by each truck when working together.

Let's denote the number of trips required by the first truck as x and the number of trips required by the second truck as y.

The first truck's rate can be expressed as 120 tons / 40 trips = 3 tons per trip. The second truck's rate can be expressed as 120 tons / 24 trips = 5 tons per trip.

Using this information, we can set up the equations: 3x + 5y = 120 (total tons of sand) x + y = total number of trips

Solving these equations, we can find the values of x and y.

I hope this helps! If you have any further questions or need additional assistance, feel free to ask.