Question

В сентябре строительная фирма покупала на заводе кирпич по некоторой цене. В октябре цена на кирпич выросла на 30%,а фирма купила на 10% кирпича меньше,чем в сентябре. На сколько процентов больше заплатила за кирпич строительная фирма в октябре, чем в сентябре? Ответ укажите а процентах

Answer 1

100%+30%=130% цена за кирпич в октябре по отношению к сентябрю
100%-10%=90% кирпича куплено в октябре по отношению к сентябрю
130%*90%:100%=117% - стоимость купленного кирпича в октябре
                                           по сравнению с сентябрём
117%-100%=17% - на столько % больше заплатили за кирпич
                                в октябре, чем в сентябре
Ответ: на 17% больше

Решение можно представить, также, в виде таблицы, переведя заранее %-ты в десятичные дроби
                                                   
                                сентябрь                      октябрь
Цена                               х                                1,3х
Количество                    у                                 0,9у
Стоимость                     ху                               1,3х*0,9у=1,17ху

Итак, видно, что стоимость кирпича в октябре возросла в 1,17 раза.
Переводим в %-ты: (1,17-1)*100%=17%
Ответ: Строительная фирма заплатила за кирпич в октябре на 17% больше, чем в сентябре

Answer 2

Calculating the Increase in Brick Price

In September, the construction company purchased bricks at a certain price. In October, the price of bricks increased by 30%, and the company bought 10% fewer bricks than in September. We need to calculate the percentage increase in the price of bricks in October compared to September.

Let's calculate the increase step by step.

1. Calculate the Total Expenditure in September: - Let's assume the price of 1 brick in September was $1. - If the company bought x bricks in September, the total expenditure in September was $1 * x.

2. Calculate the Total Expenditure in October: - The price of bricks in October increased by 30%, so the new price is $1 + 30% of $1. - The company bought 10% fewer bricks in October, so the quantity of bricks bought in October is 90% of x. - The total expenditure in October is the new price * 90% of x.

3. Calculate the Percentage Increase: - The percentage increase in expenditure is given by the formula: \[ \text{Percentage Increase} = \frac{\text{New Expenditure} - \text{Old Expenditure}}{\text{Old Expenditure}} \times 100\]

Let's calculate the percentage increase in the price of bricks in October compared to September.

Calculation

1. Total Expenditure in September: - Let's assume the price of 1 brick in September was $1. - If the company bought x bricks in September, the total expenditure in September was $1 * x.

2. Total Expenditure in October: - The price of bricks in October increased by 30%, so the new price is $1 + 30% of $1 = $1.30. - The company bought 10% fewer bricks in October, so the quantity of bricks bought in October is 90% of x. - The total expenditure in October is $1.30 * 90% of x.

3. Percentage Increase: - The percentage increase in expenditure is given by the formula: \[ \text{Percentage Increase} = \frac{\text{New Expenditure} - \text{Old Expenditure}}{\text{Old Expenditure}} \times 100\]

- Let's calculate the percentage increase using the above formula.

Calculation

1. Total Expenditure in September: - Let's assume the price of 1 brick in September was $1. - If the company bought x bricks in September, the total expenditure in September was $1 * x = $x.

2. Total Expenditure in October: - The price of bricks in October increased by 30%, so the new price is $1 + 30% of $1 = $1.30. - The company bought 10% fewer bricks in October, so the quantity of bricks bought in October is 90% of x = 0.9x. - The total expenditure in October is $1.30 * 0.9x = $1.17x.

3. Percentage Increase: - The percentage increase in expenditure is given by the formula: \[ \text{Percentage Increase} = \frac{\text{New Expenditure} - \text{Old Expenditure}}{\text{Old Expenditure}} \times 100\] \[ \text{Percentage Increase} = \frac{($1.17x - $x)}{$x} \times 100\] \[ \text{Percentage Increase} = \frac{($0.17x)}{$x} \times 100\] \[ \text{Percentage Increase} = 17\% \]

Answer

The construction company paid 17% more for bricks in October compared to September.