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Darya [45]
3 years ago
6

A woman has eight keys on a key ring, one of which fits the door she wants to unlock. Sherandomly selects a key and tries it. If

it does not unlock the door, she randomly selects anotherkey from those remaining and tries to unlock the door with it. She continues in this manner untilthe door is unlocked. Let X be the number of keys she tries before unlocking the door, countingthe key that actually worked.
Required:
Find the expected number of keys she will try before she opens the door.
Mathematics
1 answer:
natulia [17]3 years ago
3 0

Answer:

The expected number of keys she will try before she opens the door is 4.5.

Step-by-step explanation:

A woman has eight keys on a key ring, one of which fits the door she wants to unlock.

Each of them is equally as likely to be the one to work, which means that this situation is represented by an uniform distribution with lower bound a = 1 and upper bound b = 8.

Find the expected number of keys she will try before she opens the door.

The expected value of the uniform distribution is given by:

E = \frac{a + b}{2}

Considering a = 1, b = 8, as is the case in this exercise:

E = \frac{1 + 8}{2} = 4.5

The expected number of keys she will try before she opens the door is 4.5.

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The conditional probability formula tells you ...

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What is bigger 1/5 or .29
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.29 is bigger.

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Katyanochek1 [597]

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125 tickets were sold for the jazz band concert for a total of $1,022. Students tickets cost $6 each, and general admission tick
rodikova [14]

Answer:

Number of student tickets sold are 57 and general tickets sold are 68.

Step-by-step explanation:

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Also, students tickets is sold for $6 each and the general tickets are sold for $10 each.

Since, the total cost of the tickets is $1022.

So, we get,

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i.e. y = 57

Hence, the number of student tickets sold are 57 and general tickets sold are 68.

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3 years ago
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