Respuesta :
If every single student met one an another, then you would hear 90 hi's. Since there are 45 different combinations of 2 students meeting another, and since there are 2 hi's each meeting, there would be 90.
I hope that this helps.
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I hope that this helps.
Please rate me as Brainliest so I can rank up :D
The combination helps us to know the number of ways an object can be arranged without a particular manner. Before the class starts, the number of times one hears the word “hi” is 45.
What is Combination?
The combination helps us to know the number of ways an object can be arranged without a particular manner. A combination is denoted by 'C'.
[tex]^nC_r = \dfrac{n!}{(n-r)!r!}\[/tex]
where,
n is the number of choices available,
r is the choices to be made.
As there are ten kids in the class and each says “hi” to the other and the answer “hi” follows. Therefore, there will be a pair of 2 children saying hi to each other, and this pair will be formed from 10 children that are present in the class. Thus, it can be concluded that the number of times a student hears hi will be the number of possible ways two children can be selected from the class of 10. Therefore,
Number of "Hi" a student hear = ¹⁰C₂ = (10!)/2!(10-2)! = (10!)/(2!×8!) = 45
Hence, Before the class starts, the number of times one hears the word “hi” is 45.
Learn more about Combination:
https://brainly.com/question/11732255
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