There are 7 mysteries, 9 biographies, 2 reference books,and 10 picture books in the book bin at the library. What are the odds of drawing a mystery book from the bin?please help me answer this...

There are 7 mysteries, 9 biographies, 2 reference books,and 10 picture books in the book bin at the library.

What are the odds of drawing a mystery book from the bin?

please help me answer this question.

Asked on by maganda123

5 Answers | Add Yours

cburr's profile pic

cburr | Middle School Teacher | (Level 2) Associate Educator

Posted on

To figure out the probability (odds) of something happening, what you have to do is count up ALL the possibilities, and then count up how many of them involve the result you are looking for.

In this case, there are 28 different books, so there is a total of 28 possibilities of what book will be drawn from the bin.   Since 7 of the books are mysteries, 7 out of the 28 possibilities will be mysteries.  From a math standpoint, this is 7:28 or 7 out of 28.  Since 7 goes evenly into 28 (4 x 7 = 28), you can reduce it to 1:4 or 1 out of 4.  

It is important to remember that the probability is what would happen on average if you tried it many, many times.  You can't be sure that 1 of the first 4 books you actually pull on one try will be a mystery.  1 out of 4 is just the probable result.

mrschamp's profile pic

mrschamp | Elementary School Teacher | eNotes Newbie

Posted on

You need to find the total of the books.  Add the following 7 + 9 + 2 + 10 and you get 28.  Then you need to look at the problem and see that there are 7 mystery books.  Probability is written in fractions.  The numerator (top number) is the number of mystery books.  The denominator is the total number of books.  That makes you have the fraction 7/28.  You reduce that to 1/4.

revolution's profile pic

revolution | College Teacher | (Level 1) Valedictorian

Posted on

There are 7+9+2+10=28 books in total, and there are only 7 mystery books,

P(mystery books)= 7/28=1/4 (simplified form).

plfoster's profile pic

plfoster | High School Teacher | eNotes Newbie

Posted on

1 in 4....There are 28 books total...there are 7mysterys to the 28 total....so your chances of drawing a mystery would be 7 in 28 if it is reduced it would be 1 in 4.

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