Question

permutations : teacher must arrange 5 tunes for band. she has 20 tunes to choose from. how many arrangements are possible?

Answer 1

do you know how to compute this using the counting principle?

Answer 2

you have 20 choices for the first one
then 19 for the second
18 for the third
17 for the fourth
16 for the fifth

Answer 3

can we not do the counting principle?? there's a formula.. nPr

Answer 4

counting principle says the number of ways to do these together is the product
i.e. multiply them

Answer 5

the formula \(_nP_r\) is just an encapsulation of the counting principle for this type of problem
it is based on the counting principle

Answer 6

don't get married to the formula, just think
\[20\times 19\times 18\times 17\times 16\]

Answer 7

that's not the answer though.. 20

Answer 8

20!

Answer 9

the answer is much smaller

Answer 10

1860480 is answer