Question
Mathematics Question on Sets
In a group of 500 students, there are 475 students who can speak Hindi and 200 can speak Bengali. What is the number of students who can speak Hindi only ?
A
275
B
300
C
325
D
350
Answer
300
Explanation
Solution
Total number of students = 500 Let H be the set showing number of students who can speak Hindi = 475 and B be the set showing number of students who can speak Bengali = 200 So, n (H) = 475 and n (B) = 200 and given that n (B ∪ H) = 500 we have n (B ∪ H) = n (B) + n (H) - n (B ∩ H) ⇒ 500 = 200 + 475 - n (B ∩ H) so, n (B ∪ H) = 175 Hence, persons who speak Hindi only = n (H) - n ∩ H) = 475 - 175 = 300