Question

Ella and Iris are planning trips to nine countries this year. There are 12 countries they would like to visit. They are deciding which countries to skip, how many ways are there?

Answer 1

Using the combination formula, it is found that there are 220 ways to decide which countries to skip.

The order in which the countries are skipped is not important, hence the combination formula is used to solve this question.

What is the combination formula?

$C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by:

$C_{n,x} = \frac{n!}{x!(n-x)!}$

In this problem, 3 countries are skipped from a set of 12, hence the number of ways is given by:

$C_{12,3} = \frac{12!}{3!9!} = 220$

More can be learned about the combination formula at brainly.com/question/25821700

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