Answer:
120
Step-by-step explanation:
The number of ways to select [tex]r[/tex] things from a group of [tex]n[/tex] things is given by the combination formula.
[tex]nCr=\frac{n!}{r!(n-r)!}[/tex]
Where n! means n*(n-1)*(n-2)....
- There are 10 total books, so n = 10
- you have to choose 3 books, so r = 3
Plugging these into the formula gives us:
[tex]10C3=\frac{10!}{3!(10-3)!}=\frac{10*9*8*7*6*5*4*3*2*1}{(3*2*1)(7*6*5*4*3*2*1)}=\frac{10*9*8}{3*2*1}=120[/tex]
Hence, there can be 120 different groups of 3 books that u can choose from 10 books total.
