There are m boys and 12 girls in a class what is the probability of selecting of random 1 a girl 2 a boy from class
first a boy, take him out to the principal's office, then a girl?
m + 12 students
boy first
m/(m+12)
now we have (m-1)+12 students
pick a girl
12/(m+11)
so the product is
12m/[(m+12)(m+11)]
or
12m/(m^2 + 23m + 132)
To calculate the probability of selecting a girl and then a boy from the class, you need to consider the total number of possible outcomes.
Step 1: Calculate the total number of students in the class
Total number of students = m (boys) + 12 (girls) = m + 12
Step 2: Calculate the probability of selecting a girl
The probability of selecting a girl is the number of girls in the class divided by the total number of students in the class:
Probability of selecting a girl = 12 / (m + 12)
Step 3: After selecting a girl, the number of boys decreases by one, so the number of possible outcomes for selecting a boy becomes (m-1).
Step 4: Calculate the probability of selecting a boy after selecting a girl
The probability of selecting a boy after selecting a girl is the number of boys left in the class divided by the total number of students remaining:
Probability of selecting a boy = (m-1) / (m + 11)
Step 5: Calculate the overall probability of selecting a girl and then a boy
To calculate the overall probability, multiply the probability of selecting a girl by the probability of selecting a boy:
Overall probability = Probability of selecting a girl * Probability of selecting a boy
Overall probability = (12 / (m + 12)) * ((m-1) / (m + 11))
Therefore, the probability of randomly selecting a girl and then a boy from the class is (12 / (m + 12)) * ((m-1) / (m + 11)).
To calculate the probability of selecting a random girl or boy from the class, we need to determine the total number of students in the class.
From the given information, we know that there are m boys and 12 girls in the class. Therefore, the total number of students in the class is given by:
Total students = m (boys) + 12 (girls)
Now, let's calculate the probability of selecting a random girl:
P(selecting a girl) = (number of girls) / (total number of students)
P(selecting a girl) = 12 / (m + 12)
Next, let's calculate the probability of selecting a random boy:
P(selecting a boy) = (number of boys) / (total number of students)
P(selecting a boy) = m / (m + 12)
Please note that the probabilities of selecting a girl and a boy are mutually exclusive events since we are selecting only one student at random. So, to calculate the probability of selecting either a girl or a boy, we can simply add the individual probabilities:
P(selecting a girl or a boy) = P(selecting a girl) + P(selecting a boy)
P(selecting a girl or a boy) = 12 / (m + 12) + m / (m + 12)
Simplifying the expression further is not possible without knowing the specific value of 'm'.