What is the probability that if a student chosen at random is Japanese, it is also a boy in the following case?
A language class has 100 students of which 60 are from Japan, and 10 of the Japanese students are boys.
According the question, there are 100 students in a class, with 60 Japanese students and 10 of the Japanese students are boys. We need to find the probability of any student who is picked and who turns out to be Japanese also being a boy.
This is a problem of conditional probability. We are given the condition that the student picked is Japanese and have to find out the probability that he is a boy.
Now if the event that a student is Japanese is denoted as B and the event that he is a boy is denoted as A.
P (A|B) = P (A and B)/ P (B)
=> (10/100) / ((60/100)
=> 10 / 60
Therefore the required probability is 1/6.
The total number of the students in the class is 100.
The number stundents who are Japanese among the 100 students = 60.
The number of students who are boys among the Japanese sttudents = 10.
Since the choice random , the probabilty of any student being cosen is equally likely and ,therefore, 1/100.
Therefore there being 60 Japanese students among the 100, the probability of the student chosen is Japanese, is (1/100)*60 = 0.6 .
Since the are 10 Japapanese boy students, the probabilty that the chosen student is a Japanese student is equal to 10/100 = 0.1.