Question

In a group of students, 100 students know Hindi, 50 know English and 25 know both. Each of

the students knows either Hindi or English. How many students are there in the group?

Answer 1

Answer 
Let H and E is the set of students who know Hindi and English respectively. 
n(H) = 100, n(E) = 50 and n(H ∩ E) = 25 
Use formula 
n ( H ∪ E ) = n (H ) + n ( E ) – n ( H ∩ E) 
Plug the values we get, 
= [100 + 50 - 25] 
⇒ 125 
Therefore, there are 125 students in the group

Answer 2

125. because first aside 25 from each. then add the one knowing hindi and English then add the remaining 25.