The probability that he first chooses an advanced book and then chooses a beginner book is 6/121.
<h3>Probability</h3>
Given:
Beginner book=2
Intermediate book=6
Instructional piano books=11
Advanced books=3
Hence:
Probability=(2×3)÷(11×11)
Probability=6/121
Therefore the probability that he first chooses an advanced book and then chooses a beginner book is 6/121.
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Answer:
83.5
Step-by-step explanation:

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Using the arrangements formula, considering the given digits, it is found that Edward writes 6 numbers.
<h3>What is the arrangements formula?</h3>
The number of possible arrangements of n elements is given by the factorial of n, that is:

In this problem, the first digit has to be 5, while the other three are arranged, hence the total number of arrangements is given by:

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Lets look at the hours they are open from. 9 am - 4:30 pm which is 7 and a half hours a day. Now we multiply 7 1/2 by the number of days they are open, which will be 7 1/2 * 255 = 1,912.5. This means that the library is open 1,912 1/2 hours a year.
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