# Probabilities Concerning 3-Letter Sequences

• Mar 25th 2011, 07:10 AM
berkan
Probabilities Concerning 3-Letter Sequences
1)We construct a 3-letter sequence by randomly choosing the letters A and B with probabilities 2/3 and 1/3 ,respectively

a)What is the probability that we get one of ABB or ABA?

b)What is the probability that the second letter is B?

c)Suppose we win as many TL's as the number of A 's in the word (i.e 1 TL if there is one A, 2 TL if 2 A's, 3 TL if 3 A's).What is the expectation of the money we win?

d)What is the expected number of A's in the word?

Thank you so much
• Mar 25th 2011, 07:16 AM
Plato
Quote:

Originally Posted by berkan
1)We construct a 3-letter sequence by randomly choosing the letters A and B with probabilities 2/3 and 1/3 ,respectively

a)What is the probability that we get one of ABB or ABA?

b)What is the probability that the second letter is B?

c)Suppose we win as many TL's as the number of A 's in the word (i.e 1 TL if there is one A, 2 TL if 2 A's, 3 TL if 3 A's).What is the expectation of the money we win?

d)What is the expected number of A's in the word?

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• Mar 25th 2011, 07:24 AM
berkan
Hi sir

I cant do anything because of this I wrote these questions. I dont understand anything so what can I do?
• Mar 25th 2011, 07:41 AM
Plato
Quote:

Originally Posted by berkan
I cant do anything because of this I wrote these questions. I dont understand anything so what can I do?

This is not a homework service nor is it a tutorial service.
So you need a sit-down, one on one discussion with you tutor.