Question

На окружности отметели 10 чёрных и 8 зелёных точек и соединили каждую точку с каждой .Что получится если из числа всех отрезков с концами разного цвета вычесть число отрезков с одинакового цвета?

Answer 1

Нельзя писать сюда задания из олимпиады , ну я помогу
1з-----------------------1ч
2з-----------------------2ч
3з------------------------3ч
4з---------------------------4ч
5з---------------------------5ч
6з--------------------------6ч
7з---------------------------7ч
8з--------------------------8ч
ч9--------------------------10ч
То есть 1 отрезок одноцветный
10-1=9(отр)

Answer 2

Problem Analysis

We have a circle with 10 black points and 8 green points. Each point is connected to every other point on the circle. We need to determine the result of subtracting the number of line segments with different colored endpoints from the number of line segments with the same colored endpoints.

Solution

To solve this problem, we need to calculate the number of line segments with different colored endpoints and the number of line segments with the same colored endpoints.

Let's start by calculating the number of line segments with different colored endpoints. We have 10 black points and 8 green points. For each black point, there are 8 possible green endpoints, resulting in a total of 10 * 8 = 80 line segments with different colored endpoints. Similarly, for each green point, there are 10 possible black endpoints, resulting in a total of 8 * 10 = 80 line segments with different colored endpoints.

Next, let's calculate the number of line segments with the same colored endpoints. For the black points, there are 10 possible black endpoints, resulting in a total of 10 * (10 - 1) / 2 = 45 line segments with the same colored endpoints. Similarly, for the green points, there are 8 possible green endpoints, resulting in a total of 8 * (8 - 1) / 2 = 28 line segments with the same colored endpoints.

To find the final result, we subtract the number of line segments with different colored endpoints from the number of line segments with the same colored endpoints: (45 + 28) - (80 + 80) = -87.

Answer

If we subtract the number of line segments with different colored endpoints from the number of line segments with the same colored endpoints, we get a result of -87.