How many words from the Roman alphabet (26 letters) of length 45 have
up vote
-4
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How many words from the Roman alphabet (26 letters) of length 45 have
(a) No A’s?
(b) At least one A?
(c) Exactly 3 A’s?
(d) Exactly 4 B’s?
(e) Exactly 3 A’s OR exactly 4 B’s?
Not sure how to do this.
combinatorics
asked Nov 20 at 7:23
Arkitek
1
|
show 3 more comments
up vote
-4
down vote
favorite
How many words from the Roman alphabet (26 letters) of length 45 have
(a) No A’s?
(b) At least one A?
(c) Exactly 3 A’s?
(d) Exactly 4 B’s?
(e) Exactly 3 A’s OR exactly 4 B’s?
Not sure how to do this.
combinatorics
asked Nov 20 at 7:23
Arkitek
1
Let's look at the first question: How many words of length 45 can we form with $26-1 = 25$ letters? Any ideas?
– Matti P.
Nov 20 at 7:25
I think it's 25^45
– Arkitek
Nov 20 at 7:26
By "word" to you mean valid English word? Or merely string?
– David G. Stork
Nov 20 at 7:27
I think the teacher means String
– Arkitek
Nov 20 at 7:27
1
Oh... so you want us to solve your homework problem for you?
– David G. Stork
Nov 20 at 7:27
|
show 3 more comments
up vote
-4
down vote
favorite
up vote
-4
down vote
favorite
How many words from the Roman alphabet (26 letters) of length 45 have
(a) No A’s?
(b) At least one A?
(c) Exactly 3 A’s?
(d) Exactly 4 B’s?
(e) Exactly 3 A’s OR exactly 4 B’s?
Not sure how to do this.
combinatorics
asked Nov 20 at 7:23
Arkitek
1
How many words from the Roman alphabet (26 letters) of length 45 have
(a) No A’s?
(b) At least one A?
(c) Exactly 3 A’s?
(d) Exactly 4 B’s?
(e) Exactly 3 A’s OR exactly 4 B’s?
Not sure how to do this.
combinatorics
combinatorics
asked Nov 20 at 7:23
Arkitek
1
asked Nov 20 at 7:23
Arkitek
1
asked Nov 20 at 7:23
Arkitek
1
asked Nov 20 at 7:23
Arkitek
1
asked Nov 20 at 7:23
Arkitek
1
1
Let's look at the first question: How many words of length 45 can we form with $26-1 = 25$ letters? Any ideas?
– Matti P.
Nov 20 at 7:25
I think it's 25^45
– Arkitek
Nov 20 at 7:26
By "word" to you mean valid English word? Or merely string?
– David G. Stork
Nov 20 at 7:27
I think the teacher means String
– Arkitek
Nov 20 at 7:27
1
Oh... so you want us to solve your homework problem for you?
– David G. Stork
Nov 20 at 7:27
|
show 3 more comments
Let's look at the first question: How many words of length 45 can we form with $26-1 = 25$ letters? Any ideas?
– Matti P.
Nov 20 at 7:25
I think it's 25^45
– Arkitek
Nov 20 at 7:26
By "word" to you mean valid English word? Or merely string?
– David G. Stork
Nov 20 at 7:27
I think the teacher means String
– Arkitek
Nov 20 at 7:27
1
Oh... so you want us to solve your homework problem for you?
– David G. Stork
Nov 20 at 7:27
Let's look at the first question: How many words of length 45 can we form with $26-1 = 25$ letters? Any ideas?
– Matti P.
Nov 20 at 7:25
Let's look at the first question: How many words of length 45 can we form with $26-1 = 25$ letters? Any ideas?
– Matti P.
Nov 20 at 7:25
I think it's 25^45
– Arkitek
Nov 20 at 7:26
I think it's 25^45
– Arkitek
Nov 20 at 7:26
By "word" to you mean valid English word? Or merely string?
– David G. Stork
Nov 20 at 7:27
By "word" to you mean valid English word? Or merely string?
– David G. Stork
Nov 20 at 7:27
I think the teacher means String
– Arkitek
Nov 20 at 7:27
I think the teacher means String
– Arkitek
Nov 20 at 7:27
1
1
Oh... so you want us to solve your homework problem for you?
– David G. Stork
Nov 20 at 7:27
Oh... so you want us to solve your homework problem for you?
– David G. Stork
Nov 20 at 7:27
|
show 3 more comments
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Let's look at the first question: How many words of length 45 can we form with $26-1 = 25$ letters? Any ideas?
– Matti P.
Nov 20 at 7:25
I think it's 25^45
– Arkitek
Nov 20 at 7:26
By "word" to you mean valid English word? Or merely string?
– David G. Stork
Nov 20 at 7:27
I think the teacher means String
– Arkitek
Nov 20 at 7:27
1
Oh... so you want us to solve your homework problem for you?
– David G. Stork
Nov 20 at 7:27