Question

«Пирожок дороже булочки на 2 рубля, поэтому на 84рубля булочек можно купить на одну больше, чем пирожков. Сколько стоит пирожок?»

Answer 1

6руб. за пирожок
спасибо большое за информацию

Answer 2

Calculation of the Cost of a Pie

To determine the cost of a pie, let's break down the given information:

- A pie costs 2 rubles more than a bun. - With 84 rubles, you can buy one more bun than pie.

Let's assume the cost of a bun is x rubles. According to the given information, the cost of a pie would be x + 2 rubles.

Now, let's calculate the number of buns and pies that can be bought with 84 rubles:

- With 84 rubles, you can buy 84 / x buns. - With 84 rubles, you can buy 84 / (x + 2) pies.

According to the given information, the number of buns is one more than the number of pies. Therefore, we can set up the following equation:

84 / x = (84 / (x + 2)) + 1

To solve this equation, we can cross-multiply:

84(x + 2) = 84x + x(x + 2)

Expanding and simplifying the equation:

84x + 168 = 84x + x^2 + 2x

Simplifying further:

x^2 + 2x - 168 = 0

Now, we can solve this quadratic equation to find the value of x.

Using the quadratic formula: x = (-b ± √(b^2 - 4ac)) / (2a), where a = 1, b = 2, and c = -168:

x = (-2 ± √(2^2 - 4(1)(-168))) / (2(1))

Simplifying further:

x = (-2 ± √(4 + 672)) / 2

x = (-2 ± √676) / 2

x = (-2 ± 26) / 2

We have two possible solutions:

1. x = (-2 + 26) / 2 = 24 / 2 = 12 2. x = (-2 - 26) / 2 = -28 / 2 = -14

Since the cost of a bun cannot be negative, we can conclude that the cost of a bun is 12 rubles.

Therefore, the cost of a pie would be 12 + 2 = 14 rubles.

So, the cost of a pie is 14 rubles.