Page 18 - 3_Dinda Erliananda_Counting Principles

Dinda Erliananda Teaching Materials – SMA Class XII – Enumeration Rules

Example 10:

In a Mathematics test, each student is required to answer 5 questions from 8 questions
submitted. How many choices to answer the question?

Answer:
In the above case, the order of the question numbers is ignored. The problem is how many

ways are there to choose 5 questions from the 8 questions available. Choose 5 questions
from 8 questions = C(8, 5), then:

Example 11:
Of the 6 Chemistry teachers and 5 Biology teachers, 7 people will be selected as the

Science Olympiad committee. In how many ways can the selection be made if 4 of them

are chemistry teachers?
Answer:

Choose 4 out of 6 Chemistry teachers and 3 out of 5 Biology teachers.

Number of ways = C(6, 4) C(5, 3)

Example 12:

In how many different ways 7 students can be divided into three groups of 4, 2, and 1
each.

Answer:

Alternative 1:
Many different ways =

14