given:
in a group of 42 students 10 students study both, 13 study only biology and 7 study neither of the subject.
to find:
the probability of the students who studies art and biology.
solution:
A= students study art
B= students study biology
N=42
n (ANB)= 10
n (A'NB)= 13
n (A'NB')= 7
the number of students who study only art:
n (ANB')= N- n(ANB) - n(A'NB) - n(A'NB')
= 42.10 - 13 - 7
= 12
the number of students who study only art:
= 16
p (ANB)= n (ANB)/N
= 10/40
= 0.238
probability the student who studies art and biology is 0.238.