# Maths

posted by .

They are 5 boys.If each boy plays a game of chess with each of the boys, how many games will there be?

• Maths -

Each of the five boys can play against each of the other 4. which would be 20 games,
BUT, that would include the pair of games of
boy1 vs boy2 and boy2 vs boy1, the same game.
So we have to divide by 2 to eliminate all those "doubles"
There will be 10 games

The number is actually low enough for you to list them

1-2
1-3
1-4
1-5

2-3
2-4
2-5

3-4
3-5

4-5 for a total of 10

This is a typical "combination" problem where you are choosing the number of cases of "5 choose 2" or
C(5,2) = 5!/(3!2!) = 10

## Similar Questions

1. ### Math

What is 5/8 + 4/7 -1 ? I can't understand this math problem.... Please help me.... ------------------ Problem: In a boys' school, 5/8 of the boys play football and 4/7 play rugby. If every boy plays at least one of the two games, find
2. ### Maths

I can't understand this math problem.... Please help me.... ------------------ Problem: In a boys' school, 5/8 of the boys play football and 4/7 play rugby. If every boy plays at least one of the two games, find the fraction of the …
3. ### maths

in a boy's school,5/8 of the boys play football and 4/7 play rugby.if every boy play atleast one of the two games,ind the fraction of the boys who play both ?
4. ### math

in a boy's school, 5/8 of the boys play football and 4/7 play rugby.if every boy plays at least one of the two games, find the fraction of the boys who play both

Keith played some games of chess at a tournament. He recorded the results of the games on the table shown. Game Results: Number of Games TIES 4 WINS 12 Losses 4 If Keith plays 10 more games, how many of the 10 games is he likely to …
6. ### Science

Whenever Adrian plays his favorite video game he always A higher score if he plays well listen to music he wants to know if listening to music while playing video games affects other kids as well he decides to test all the boys in …
7. ### writing

Both Ernesto from barrio boy and the boy in "A Day's Wait" interact with adults. Ernesto interacts with Miss Ryan, while the sick boy interacts with his father. In a paragraph, compare and contrast how the boys interact with the adults. …
8. ### Maths

In class 4A, 21 boys play cricket, 16 boys play football. 13 play both games. What is the smallest number of boys in that class
9. ### LA Help!

Both Ernesto from barrio boy and the boy in "A Day's Wait" interact with adults. Ernesto interacts with Miss Ryan, while the sick boy interacts with his father. Compare and contrast how the boys interact with the adults. Focus on how …
10. ### Language arts

Both Enersto from Barrion Boy and the boy in a days wait interact with adults. Ernesto interacts with Miss Ryan, while the sick boy interacts with his father.In a paragraph, compare and contrast how the boys interact with adults. Focus …

More Similar Questions