98.7k views
3 votes
Determine the number of ways to choose a set of 9 pencils from a selection of 10.

User Lionel B
by
8.9k points

2 Answers

1 vote
label the pencils:
a b c d e f g h i j
choosing 9 of them will exclude one. There are 10 pencils, so 10 opportunities to exclude one of them. So there are 10 ways, to answer your question.
User Ftkg
by
7.9k points
5 votes

Answer:

The number of ways to choose a set of 9 pencils from a selection of 10 is 10.

Explanation:

According to the combination formula, the total number of ways to select r items from total n items is


^nC_r=(n!)/(r!(n-r)!)

Total number of pencils = n = 10

Number of selected pencils = r = 9

The number of ways to choose a set of 9 pencils from a selection of 10 is


^(10)C_(9)=(10!)/(9!(10-9)!)


^(10)C_(9)=(10* 9!)/(9!1!)


^(10)C_(9)=10

Therefore the number of ways to choose a set of 9 pencils from a selection of 10 is 10.

User Mofeeta
by
8.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories