Question

Человек за первый час пути прошёл 4 5/12 к, за второй час - на 1 2/3 км больше, чем за первый час, а за третий час он прошёл на 2 3/4 км меньше, чем за второй час. Определи, сколько километров человек прошёл за третий час. Срочно.

Answer 1

Ответ:

3 1/3 км

Пошаговое объяснение:

1ч - 4 5/12

2ч - 4 5/12 +1 2/3

3ч - 4 5/12 + 1 2/3 - 2 3/4 = 3 1/3 км

Answer 2

Problem Analysis

We are given information about a person's travel over three hours. In the first hour, the person traveled 4 5/12 km. In the second hour, they traveled 1 2/3 km more than in the first hour. In the third hour, they traveled 2 3/4 km less than in the second hour. We need to determine how many kilometers the person traveled in the third hour.

Solution

To solve this problem, we can break it down into steps:

1. Calculate the distance traveled in the second hour. 2. Calculate the distance traveled in the third hour.

Let's calculate the distance traveled in the second hour:

In the second hour, the person traveled 1 2/3 km more than in the first hour. To find the distance traveled in the second hour, we can add 1 2/3 km to the distance traveled in the first hour.

The distance traveled in the first hour is 4 5/12 km. Adding 1 2/3 km to this gives us:

4 5/12 km + 1 2/3 km = 4 5/12 km + 4/3 km

To add these fractions, we need to find a common denominator. The common denominator of 12 and 3 is 12. Let's convert the fractions to have a denominator of 12:

4 5/12 km + 1 2/3 km = 4 5/12 km + 4/3 km = 4 5/12 km + (4/3) * (4/4) km = 4 5/12 km + 16/12 km = (4 + 16)/12 km = 20/12 km

Simplifying the fraction, we get:

20/12 km = 10/6 km = 5/3 km

Therefore, the person traveled 5/3 km in the second hour.

Now, let's calculate the distance traveled in the third hour:

In the third hour, the person traveled 2 3/4 km less than in the second hour. To find the distance traveled in the third hour, we can subtract 2 3/4 km from the distance traveled in the second hour.

The distance traveled in the second hour is 5/3 km. Subtracting 2 3/4 km from this gives us:

5/3 km - 2 3/4 km

To subtract these fractions, we need to find a common denominator. The common denominator of 3 and 4 is 12. Let's convert the fractions to have a denominator of 12:

5/3 km - 2 3/4 km = 5/3 km - 11/4 km

To subtract these fractions, we need to find a common denominator. The common denominator of 3 and 4 is 12. Let's convert the fractions to have a denominator of 12:

5/3 km - 2 3/4 km = 5/3 km - 11/4 km = (5/3) * (4/4) km - (11/4) * (3/3) km = 20/12 km - 33/12 km = (20 - 33)/12 km = -13/12 km

Therefore, the person traveled -13/12 km in the third hour.

Answer

The person traveled -13/12 km in the third hour.

Note: The negative distance indicates that the person traveled in the opposite direction during the third hour.