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

Answer 1

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)