Question

Срочно,пожалуйсто!! 1 задача. За 4 зошити і дві ручки заплатили 36грн.Стільки ж коштують 3 зошити і 4 ручки.Яка ціна одного зошита і однієї ручки? 2 задача. На виготовлення 160 столових і 200 чайних ложок витратили 14кг.срібла.Яка маса однієї чайної ложки,якщо з столової ложки мають таку саму масу,як 5 чайних ложок?

Answer 1

Ответ:

первая задача в прикреплённом файле, вот вторая:

х- маса столової ложки

3х- маса трьох столових ложок

3х/5- маса чайної ложки

160х+200*3х/5=14

160+120х=14

280х=14

х=0,05

Маса столової ложки- 0,05 кг

Маса чайної ложки- 0,03

х- маса  столової  ложки

у- маса чайної ложки

                                                                        280х+14000

160х+200у=14000     160х+200у=14000      х=50

3х=5у                           120х-120у=0               120*50=200у

                                                                         у=30

Відповідь: 50г, 30г.

Answer 2

Problem 1: Cost of notebooks and pens

To find the cost of one notebook and one pen, we can set up a system of equations based on the given information.

Let's assume the cost of one notebook is x and the cost of one pen is y.

From the first statement, we know that 4 notebooks and 2 pens cost 36 UAH. This can be expressed as the equation:

4x + 2y = 36 [[1]]

From the second statement, we know that 3 notebooks and 4 pens cost the same amount. This can be expressed as the equation:

3x + 4y = 36 [[2]]

To solve this system of equations, we can use the method of substitution or elimination. Let's use the elimination method.

Multiplying equation [[1]] by 2 and equation [[2]] by 3, we get:

8x + 4y = 72 [[3]] 9x + 12y = 108 [[4]]

Subtracting equation [[3]] from equation [[4]], we eliminate the variable y:

9x + 12y - (8x + 4y) = 108 - 72 x + 8y = 36 [[5]]

Now we have a new equation with only one variable. We can solve it for x.

Subtracting 8y from both sides of equation [[5]], we get:

x = 36 - 8y [[6]]

Now we can substitute the value of x from equation [[6]] into either equation [[1]] or [[2]] to solve for y.

Let's substitute it into equation [[1]]:

4(36 - 8y) + 2y = 36 144 - 32y + 2y = 36 -30y = -108 y = 3.6

Now we can substitute the value of y back into equation [[6]] to find x:

x = 36 - 8(3.6) x = 36 - 28.8 x = 7.2

Therefore, the cost of one notebook is 7.2 UAH and the cost of one pen is 3.6 UAH.

Problem 2: Mass of a teaspoon

To find the mass of one teaspoon, we can set up a proportion based on the given information.

Let's assume the mass of one teaspoon is x kg.

From the given information, we know that 160 tablespoons and 200 teaspoons together weigh 14 kg. This can be expressed as the equation:

160x + 200(x/5) = 14 [[7]]

Simplifying equation [[7]], we get:

160x + 40x = 14 200x = 14 x = 14/200 x = 0.07

Therefore, the mass of one teaspoon is 0.07 kg.

Please let me know if you need any further assistance!