Question

A bookstore classifies its books by reader group, type of book, and cost. What is the probability that a book selected at random is a child’s book, given that it costs $15?

< $10 > $10
Child Fiction 120 255
Nonfiction 35 60
Adult Fiction 200 110
Nonfiction 75 150
A. 3151005
B. 4701005
C. 315575
D. 470575

Answer 1

Pr(Cb) & Pr(cost $15) = 15(Ncb)/(T1×T3)

Step-by-step explanation:

Classification of the book in to 3

First let's assign terms to each probability

Let:

T1= total number of type of Reader's group

T2 = total number of Type of book

T3 = total number of type of Cost

Probability of child's book and cost $15= Pr(Cb) & Pr(cost $15)

Then find probability of child's book and cost separately:

Pr of child's book = Pr(Cb)

Pr(Cb) = (number of child's book)/ total number of type of group

Ncb = number of child's book

Pr(Cb) = Ncb/T1

Pr (cost $15) = $15 book/total number of cost

Pr (cost $15) = 15/T3

probability of child's book and cost $15 = Pr(Cb) × Pr (cost $15)

= Ncb/T1 × 15/T3

Pr(Cb) & Pr(cost $15) = 15(Ncb)/(T1×T3)

Answer 2

A) 315/1005

Step-by-step explanation:

Total choices: 120 + 255 + 35 + 60 + 200 + 110 + 75 + 150 = 1005

Favorable choices: 255 + 60 = 315

probability:

favorable choices/total choices

315/1005

21/67