There are 21 ways Tim choose 2 books from the 7 recommended book
<em><u>Solution:</u></em>
Given that Tim must read 2 books from a list of 7 recommended books for his summer reading program
To find: different ways can Tim choose 2 books from the 7 recommended books
This is a combination problem
A combination is a selection of all or part of a set of objects, without regard to the order in which objects are selected
<em><u>The formula for combinations is:</u></em>
where n represents the number of items, and r represents the number of items being chosen at a time
Here we have to choose 2 books from 7 books
Therefore, n = 7 and r = 2
<em><u>Substituting values in above formula, we get</u></em>
For a number n, the factorial of n can be written as,
Therefore, we get
Thus there are 21 ways Tim choose 2 books from the 7 recommended book