Question

КОРОНА ЕСЛИ ОТВЕТИТЕ ПРАВИЛЬНО И БЫСТРО_)) пОМОГИТЕЕЕЕЕЕЕЕЕЕ_) Две пары обуви и три рубашки стоят 230 леев, а 3 пары обуви и две рубашки стоят 270 леев.Сколько стоит 7 пар обуви и рубашку? Пожалуста помогите дам корону))_

Answer 1

Обувь стоит х
рубашка стоит у

составляем 2 уравнения
2х+3у=230
3х+2у=270

из 1 уравнения выражаем х
х=(230-3у):2
подставляем во 2 уравнение
3*(230-3у):2+2у=270
(690-9у):2+4у/2=270
690-9у+4у=270*2
-5у=540-690
-5у=-150
у=30 (л) - стоит рубашка

х=(230-3у):2=(230-30*3):2=140:2=70 (л) - стоит обувь

Answer 2

Problem Analysis

We are given the prices of two pairs of shoes and three shirts, as well as the prices of three pairs of shoes and two shirts. We need to determine the cost of seven pairs of shoes and one shirt.

Solution

Let's assign variables to the unknowns: - Let x be the cost of one pair of shoes. - Let y be the cost of one shirt.

From the given information, we can set up the following equations:

Equation 1: 2x + 3y = 230 (equation representing the cost of two pairs of shoes and three shirts)

Equation 2: 3x + 2y = 270 (equation representing the cost of three pairs of shoes and two shirts)

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

From Equation 1, we can express y in terms of x:

2x + 3y = 230

3y = 230 - 2x

y = (230 - 2x)/3

Now, substitute this expression for y in Equation 2:

3x + 2((230 - 2x)/3) = 270

Simplify and solve for x:

3x + (460 - 4x)/3 = 270

Multiply through by 3 to eliminate the fraction:

9x + 460 - 4x = 810

5x = 810 - 460

5x = 350

x = 350/5

x = 70

Now, substitute the value of x back into Equation 1 to find y:

2(70) + 3y = 230

140 + 3y = 230

3y = 230 - 140

3y = 90

y = 90/3

y = 30

Therefore, one pair of shoes costs 70 leev and one shirt costs 30 leev.

To find the cost of 7 pairs of shoes and one shirt, we can calculate:

Cost = (7 * x) + y

Cost = (7 * 70) + 30

Cost = 490 + 30

Cost = 520 leev

The cost of 7 pairs of shoes and one shirt is 520 leev.