Question

Подоходный налог составляет 13% от заработной платы. После удержания налога на доходы Павел Викторович получил 6090 руб. Сколько рублей составляет его зарплата?После подорожания на 25% 1 кг черешни стал стоить 120 руб. Сколько стоил 1кг черешни до подорожания? Смешали 25л воды и 10л 14% -го раствора соляной кислоты. Сколько процентов составляет концентрация соляной кислоты в растворе?

Answer 1

1)   100 %   -  х руб.
(100-13) %  - 6090 руб.
(100-13) х = 6090 *100
87х =609000
х=609000:87
х=7000 (руб.)  
Ответ: 7000 руб. составляет зарплата до вычета подоходного налога.

2)
(100+25) %   - 120 руб.
100% - х руб.
125х= 120*100
125х=12000
х=12000:125
х= 96 (руб.) 
Ответ: 96 руб.  стоил 1 кг черешни до подорожания

3) 14% = 14/100 = 0,14
0,14 *10 = 1,4  кислоты в растворе
1,4  / (10+25) = 1,4 /35 = 0,04  ⇒  4% 
Ответ: 4% составляет концентрация кислоты в растворе.

Answer 2

Calculation of Pavel Viktorovich's Salary

To calculate Pavel Viktorovich's salary, we need to determine the amount before the income tax was deducted. We know that the income tax rate is 13% and that Pavel Viktorovich received 6090 rubles after the deduction.

Let's denote Pavel Viktorovich's salary before the deduction as x. We can set up the following equation:

x - (13% of x) = 6090

To solve this equation, we can express 13% as a decimal by dividing it by 100:

x - (0.13 * x) = 6090

Simplifying the equation:

0.87 * x = 6090

Dividing both sides of the equation by 0.87:

x = 6090 / 0.87

Evaluating the expression:

x ≈ 7000

Therefore, Pavel Viktorovich's salary before the income tax deduction is approximately 7000 rubles.

Calculation of the Original Price of Cherries

To calculate the original price of cherries before the 25% increase, we need to determine the price after the increase. We know that after the increase, 1 kg of cherries costs 120 rubles.

Let's denote the original price of 1 kg of cherries as x. We can set up the following equation:

x + (25% of x) = 120

To solve this equation, we can express 25% as a decimal by dividing it by 100:

x + (0.25 * x) = 120

Simplifying the equation:

1.25 * x = 120

Dividing both sides of the equation by 1.25:

x = 120 / 1.25

Evaluating the expression:

x = 96

Therefore, the original price of 1 kg of cherries before the increase was 96 rubles.

Calculation of the Concentration of Hydrochloric Acid in the Solution

To calculate the concentration of hydrochloric acid in the solution, we need to determine the percentage concentration. We know that 25 liters of water were mixed with 10 liters of a 14% hydrochloric acid solution.

Let's denote the concentration of hydrochloric acid in the solution as