Question

Цена телефона марки А в магазине в сентябре повысилась на 5%. А в октябре понизилась на 4%, и он стал стоит 15120рублей. найдите первоначальную цену телефона.

Answer 1

1) 15120 : 100 * 5 = 756 
2) 756*100:4= 18900 
вроде так 

Answer 2

Calculation of the Initial Price of the Phone

To find the initial price of the phone, we can use the given information about the price changes in September and October. Let's assume the initial price of the phone is represented by the variable x.

According to the information provided, the price of the phone increased by 5% in September and then decreased by 4% in October. After these changes, the phone is priced at 15,120 rubles.

To calculate the initial price, we can follow these steps:

1. Calculate the price after the 5% increase in September: - Price after the increase = x + (5% of x) - Price after the increase = x + 0.05x - Price after the increase = 1.05x

2. Calculate the price after the 4% decrease in October: - Price after the decrease = 1.05x - (4% of 1.05x) - Price after the decrease = 1.05x - 0.04(1.05x) - Price after the decrease = 1.05x - 0.042x - Price after the decrease = 1.008x

3. Set up an equation using the final price of 15,120 rubles: - 1.008x = 15,120

4. Solve the equation for x: - x = 15,120 / 1.008 - x ≈ 14,999.21

Therefore, the initial price of the phone was approximately 14,999.21 rubles.

Please note that the calculated value is an approximation due to rounding in the final step of the calculation.