Question

Серёжа ехал на велосипеде 3 часа. За первый час он проехал пятую часть всего пути, за второй час - половину оставшегося пути, а в третий час - оставшегося пути, а в третий час - оставшиеся 12 км. Какова длина пути только без иксов

Answer 1

После первого часа осталось проехать 1 - 1/5 = 4/5 пути. За второй час ог проехал половину этого остатка, т.е 4/5 : 2 = 2/5 пути.  Сталось 4/5 - 2/5 = 2/5 пути, которые он проехал за третий час.

Значит 2/5 пути равны 12км. Чтобы найти весь путь, нужно величину дроби разделить на саму дробь, т.е. 12 : 2/5= 12 * 5/2 = 30 км. Это и есть весь путь.

Answer 2

Calculation of the Distance Traveled

To find the length of the entire journey, we can break down the information provided:

- In the first hour, Sergey traveled one-fifth of the total distance. - In the second hour, he traveled half of the remaining distance. - In the third hour, he traveled the remaining distance, which is given as 12 km.

Let's calculate the distance traveled in each hour and then sum them up to find the total distance.

1. Distance traveled in the first hour: one-fifth of the total distance. 2. Distance traveled in the second hour: half of the remaining distance after the first hour. 3. Distance traveled in the third hour: the remaining distance, which is given as 12 km.

Let's calculate the distances:

1. Distance traveled in the first hour: (1/5) * x (where x is the total distance). 2. Distance traveled in the second hour: (1/2) * (4/5) * x (since Sergey has already traveled one-fifth of the total distance in the first hour, only four-fifths remain). 3. Distance traveled in the third hour: 12 km.

To find the total distance, we need to sum up the distances traveled in each hour:

[(1/5) * x] + [(1/2) * (4/5) * x] + 12 = x

Now, let's solve this equation to find the value of x, which represents the total distance traveled by Sergey.

To solve the equation, we can simplify it step by step:

[(1/5) * x] + [(1/2) * (4/5) * x] + 12 = x

Simplifying the equation:

[(1/5) * x] + [(2/5) * x] + 12 = x

Combining like terms:

[(1/5) * x + (2/5) * x] + 12 = x

Multiplying both sides of the equation by 5 to eliminate the fractions:

x + 2x + 60 = 5x

Simplifying:

3x + 60 = 5x

Subtracting 3x from both sides:

60 = 2x

Dividing both sides by 2:

x = 30

Therefore, the total distance traveled by Sergey is 30 km.

Please note that the value of x represents the total distance traveled by Sergey, and it does not include any "x" variables mentioned in the question.