Answer:
The probability that all 15 will get the type of book they want from current stock is 0.4838.
Step-by-step explanation:
I think your question is missed of key information, allow me to add in and hope it will fit the original one.
<em>Suppose that 30% of all students who have to buy a text for a particular course want a new copy (the successes!), whereas the other 70% want a used copy. Consider randomly selecting 15 purchasers.
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<em>The bookstore has 10 new copies and 10 used copies in stock.
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<em>If 15 people come in one by one to purchase this text, what is the probability that all 15 will get the type of book they want from current stock?</em>
Here is my answer:
Given:
n= 15
P (want used copy) = 0.7
P (want new copy) = 0.3
Let X = the number who want a new copy.
All the 15 students get their desired copy, then this can happen if at most 10 want to buy new copy and at least 5 wants to buy used copy.
So compute the probability of (5 ≤ X ≤ 10) as follows:
P (5 ≤ X ≤ 10) = P (X = 5) + P (X = 6) + P (X = 7) + P (X = 8) + P (X = 9) + P (X = 10)
= * * + + + + +
= 0.4838
So the probability that all 15 will get the type of book they want from current stock is 0.4838.
Hope it will find you well.