Answer:
120
Step-by-step explanation:
If order doesn't matter, there are 10 ways to chose the first ride, 9 ways to choose the second, and 8 ways to choose the third. This product (720) has you riding the same 3 coasters in 6 different orders. Dividing by 6 gives ...
720/6 = 120 different combinations of roller coasters
_____
This number might be written as 10C3 (choose 3 from 10). The meaning of that notation is ...
nCk = n!/(k!(n-k)!)
10C3 = 10!/(3!·7!) = 10·9·8/(3·2·1) = 120
Answer:
If the shelves are 4/5 full, then the total number of books in the library is 1,040 books
Step-by-step explanation:
13 roll of bookcases
All the bookcases have four shelves
Total number of shelves = 4 x 13
= 52 shelves
Each shelve holds 25 books each
Total number of books that can be in the shelves altogether = 52 x 25
= 1,300 books
If the shelves are 4/5 full, then the total number of books in the library is,
4/5 x 1300
= 1,040 books
