- #1
iScience
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Homework Statement
set {A} : 26 elements <--- let's call this number n
set {B}: 24 elements <--- let's call this number m
goal: i want to know the number of possible combinations i will have if i start by replacing one element in {A} with an element in {B}, then i want to know the number of possible combinations of elements i can have if i replace two elements in {A} with any two elements in {B}. i want to do this all the way up to 24 replacements.
Homework Equations
this is what I'm trying to ultimately find.
The Attempt at a Solution
1 replacement: $$ n*m$$(since the number of elements you can replace in set A is n, and for each replaced element, there are m possible numbers in B you can replace them with)
2 replacements: $$n!(n-1)!*m(m-1)$$
(the n terms on the left deal with the placement of the A elements getting replaced. ie how many different ways can you arrange two elements throughout {A}
$$a_{1}a_{2}$$
$$a_{1}a_{3}$$
$$a_{1}a_{4}$$
$$...$$
$$a_{1}a_{n}$$
...
$$a_{2}a_{3}$$
$$a_{2}a_{4}$$
$$a_{2}a_{5}$$
etc..
and the m terms on the left: basically after you pick a b_element for any particular arrangement, you have now have b-1 elements to choose from.
)
m replacements: $$ n!(n-1)!(n-2)!(n-3)!...(n-m)!*m(m-1)(m-2)(m-3)...(1) = Π(n-i)!*m!$$
i'm very suspicious of my answer because it yields numbers that seem too big to be true