Question

за 2 блокнота, 5 карандашей и 3 ручки заплатили 119 рублей.Найди цену блокнота , карандаша и ручки, если за 2 блокнота и 5 карандашей заплатили 83 рубля, а за 5 карандашей и 3 ручки - 8 рублей

Answer 1

2x+5y+3z=119
2x+5y=83, следовательно Z=(119-83)/3=12 - цена ручки
5y+3z=80 (8  быть не может, т.к. Z*3 больше 8) (80-3*12)/5=y=8.8 - цена карандаша.
x=(83-5*8.8)/2=19.5 - цена блокнота.
x+y+z=12+8.8+19.5=40.3

Answer 2

Problem Analysis

We are given the following information: - The total cost of 2 notebooks, 5 pencils, and 3 pens is 119 rubles. - The cost of 2 notebooks and 5 pencils is 83 rubles. - The cost of 5 pencils and 3 pens is 8 rubles.

We need to find the individual prices of a notebook, a pencil, and a pen.

Solution

Let's assume the price of a notebook is x rubles, the price of a pencil is y rubles, and the price of a pen is z rubles.

From the given information, we can form the following equations:

1. 2x + 5y + 3z = 119 (equation 1) 2. 2x + 5y = 83 (equation 2) 3. 5y + 3z = 8 (equation 3)

We can solve these equations to find the values of x, y, and z.

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

From equation 2, we can express x in terms of y: 2x = 83 - 5y x = (83 - 5y) / 2

Substituting this value of x in equation 1, we get: 2 * ((83 - 5y) / 2) + 5y + 3z = 119 83 - 5y + 5y + 3z = 119 3z = 119 - 83 3z = 36 z = 36 / 3 z = 12

Now, substituting the value of z in equation 3, we get: 5y + 3 * 12 = 8 5y + 36 = 8 5y = 8 - 36 5y = -28 y = -28 / 5 y = -5.6

We have found the value of y, but since prices cannot be negative, we can conclude that there was an error in the given information or calculations.

Therefore, we cannot determine the individual prices of a notebook, a pencil, and a pen based on the given information.

Please double-check the given information or provide additional details if available.