Math Problem Statement

1. Di dalam sebuah kelas terdapat 100 mahasiswa, 40 orang diantaranya laki-laki. (a) Berapa banyak cara dapat dibentuk sebuah panitia 10-orang? (b) Ulangi pertanyaan (a) jika banyaknya laki-laki harus sama dengan banyaknya perempuan. (c) Ulangi pertanyaan (a) jika panitia itu harus terdiri dari enam laki-laki dan empat perempuan atau empat laki-laki dan enam perempuan? 2. Tunjukkan bahwa sembarang 6 kelas kuliah pasti terdapat dua kelas yang dijadwalkan pada hari yang sama, dengan asumsi tidak ada kuliah pada Hari Sabtu (akhir pekan). 3. Berapa peluang sebuah bilangan bulat yang dipilih secara acak dari 100 bilangan bulat positif pertama bernilai genap? 4. Diketahui harga beras (Rp.) pada tahun 2023 berikut: Tentukan: (a) Deviasi rata-rata beras premium, medium, dan rendah. (b) Koefisien standar deviasi (KSD) dari beras premium, medium, dan rendah.

Solution

Let’s go through each question in the image to break them down and solve as needed:

Question 1

Given: A class has 100 students, with 40 males.
You’re asked different scenarios of forming a committee of 10 students.

  1. (a) How many ways to form a 10-person committee?

    • Since there are no gender restrictions, the answer is simply the combination of 100 students taken 10 at a time: C(100,10)C(100, 10).
  2. (b) If the number of males must equal the number of females (5 males and 5 females)?

    • Here, select 5 males from 40, and 5 females from 60. The answer is the product of these two combinations: C(40,5)×C(60,5)C(40, 5) \times C(60, 5).
  3. (c) If the committee must have either 6 males and 4 females or 4 males and 6 females?

    • For the first option (6 males, 4 females): C(40,6)×C(60,4)C(40, 6) \times C(60, 4).
    • For the second option (4 males, 6 females): C(40,4)×C(60,6)C(40, 4) \times C(60, 6).
    • The answer is the sum of these two results.

Question 2

Show that in any set of 6 classes, two will have the same day scheduled (assuming no classes on Saturday).

This is a Pigeonhole Principle problem. Since there are 5 weekdays and 6 classes, at least two classes will fall on the same day, as we have more classes than available days.

Question 3

What is the probability of randomly selecting an even number from the first 100 positive integers?

  • The even numbers from 1 to 100 are {2, 4, ..., 100}, totaling 50 numbers.
  • Probability = 50100=0.5\frac{50}{100} = 0.5.

Question 4

Given the price data for rice of different qualities over several months, you are asked to:

  1. (a) Find the average price deviation for each quality (Premium, Medium, Low).

    • Calculate the mean of the prices for each quality, then find the average deviation from this mean for each month.
  2. (b) Find the standard deviation (SD) for each quality.

    • Calculate the standard deviation for the prices of each quality over the months provided.

Would you like to go deeper into any of these calculations, or should we start with specific parts?


Further Exploratory Questions:

  1. How can the combination formulas be calculated in detail for each part of question 1?
  2. What is the exact computation of probabilities using different sets in combinatorics?
  3. Can the Pigeonhole Principle apply to more complex scheduling scenarios?
  4. How does the mean deviation differ from standard deviation conceptually and computationally?
  5. What are the statistical implications of price variations in economic analyses?

Tip:

For calculating combinations C(n,k)C(n, k), use the formula C(n,k)=n!k!(nk)!C(n, k) = \frac{n!}{k!(n-k)!}.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Combinatorics
Probability
Statistics
Pigeonhole Principle

Formulas

Combination formula: C(n, k) = n! / (k!(n-k)!)
Probability formula: P = favorable outcomes / total outcomes
Standard Deviation
Mean Deviation

Theorems

Pigeonhole Principle

Suitable Grade Level

College level or advanced high school