23 Imagine that a long stretch of a singlestranded DNA has 3

23. Imagine that a long stretch of a single-stranded DNA has 30% adenine, 25% thiamine, 15% cytosine, and 30% guanine. What is the probability of randomly drawing 10 adenines in a row in a sample of 10 randomly chose nucleotides?

Solution

One must have 10 A’s in a row. That is AAAAAAAAAA.

Now, P(A)=0.25

Thus, P(10 A’s)=0.25^10=0.0000009