A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

mathmath333

  • one year ago

A class prefect goes to meet the principal every week. His class has 30 people apart from him. If he has to take groups of 3 every time he goes to the principal, in how many weeks will he be able to go to the principal without repeating the group of same 3 which accompanies him?

  • This Question is Closed
  1. mathmath333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \(\large \color{black}{\begin{align} & \normalsize \text{A class prefect goes to meet the principal every week.}\hspace{.33em}\\~\\ & \normalsize \text{His class has 30 people apart from him. If he has to take }\hspace{.33em}\\~\\ & \normalsize \text{groups of 3 every time he goes to the principal, in how }\hspace{.33em}\\~\\ & \normalsize \text{many weeks will he be able to go to the principal without }\hspace{.33em}\\~\\ & \normalsize \text{repeating the group of same 3 which accompanies him?}\hspace{.33em}\\~\\ & 1. \binom{30}{3} \hspace{.33em}\\~\\ & 2. \binom{29}{2} \hspace{.33em}\\~\\ & 3. \binom{29}{3} \hspace{.33em}\\~\\ & 4. \normalsize \text{none of these} \hspace{.33em}\\~\\ \end{align}}\)

  2. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    if youre a mathtele why post this question, but the answer is 1

  3. mathmath333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    u mean answer is 1

  4. mathmath333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    but the question is asking the number of weeks , how is this related to that ?

  5. kropot72
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Say the prefect chooses group A to accompany him on the first week. On the second week he only needs to ensure he does not pick all the same students as in group A.

  6. IrishBoy123
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    he is choosing 3 companions from 30, every week he visits the principal, so \[C_{3}^{30}\]

  7. mathmate
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    It is much less confusing to give the answer instead of the shorthand. @mitchal means choice #1, \(\left(\begin{matrix}30 \\ 3\end{matrix}\right)\) weeks because order does not count, and we need to find the number of distinct groups of three students, not including himself (31st student in the class).

  8. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    So if it doesnt included himself would it be 29/3?

  9. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.