on a library shelf, there are three geometry and five algebra books. books are replaced after someone borrow it. if two books are taken, what is the probability that the first book is geometry and the second book is algebra?
There are a total of eight books on the shelf, three of which are geometry books and five of which are algebra books. If two books are taken without replacement, there are a total of 8 x 7 = 56 possible ways that the two books can be chosen.
To calculate the probability that the first book chosen is a geometry book and the second book chosen is an algebra book, we can use the following formula:
P(G then A) = P(G) * P(A | G)
where P(G) is the probability of choosing a geometry book first, and P(A | G) is the probability of choosing an algebra book second given that the first book chosen was a geometry book.
The probability of choosing a geometry book first is 3/8, since there are three geometry books out of a total of eight books.
Once a geometry book has been chosen, there are seven books remaining, including four algebra books. Therefore, the probability of choosing an algebra book second given that the first book chosen was a geometry book is 4/7.
Therefore, the probability of choosing a geometry book first and an algebra book second is:
P(G then A) = P(G) * P(A | G)
P(G then A) = (3/8) * (4/7)
P(G then A) = 12/56
P(G then A) = 3/14
Therefore, the probability that the first book is geometry and the second book is algebra is 3/14, or approximately 0.214.
Answers & Comments
Answer:
There are a total of eight books on the shelf, three of which are geometry books and five of which are algebra books. If two books are taken without replacement, there are a total of 8 x 7 = 56 possible ways that the two books can be chosen.
To calculate the probability that the first book chosen is a geometry book and the second book chosen is an algebra book, we can use the following formula:
P(G then A) = P(G) * P(A | G)
where P(G) is the probability of choosing a geometry book first, and P(A | G) is the probability of choosing an algebra book second given that the first book chosen was a geometry book.
The probability of choosing a geometry book first is 3/8, since there are three geometry books out of a total of eight books.
Once a geometry book has been chosen, there are seven books remaining, including four algebra books. Therefore, the probability of choosing an algebra book second given that the first book chosen was a geometry book is 4/7.
Therefore, the probability of choosing a geometry book first and an algebra book second is:
P(G then A) = P(G) * P(A | G)
P(G then A) = (3/8) * (4/7)
P(G then A) = 12/56
P(G then A) = 3/14
Therefore, the probability that the first book is geometry and the second book is algebra is 3/14, or approximately 0.214.