In a school of 100 children, 50 play cricket and 60 play football. Find the probability that a student selected at random plays both the sports if each of the student plays at least one sport.
Let x be the number of students play both the sports.
Students who play only cricket = 50-x
Students who play only football = 60-x
It is given that a student plays at least one sport
100 = students who play only cricket + students who play only football +students who play both
100 = (50-x) + (60-x) +x ⇒ x =10
Probability that a student plays both the sports = 10100 = 110