In a group of 400 people, 250 can speak Hindi and 200 can speak English. How many people can speak both Hindi and English?

Solution: Here, number of people speakinhg Hindi ($n\left(A\right))=250$
Number of people speakinhg English$\left(n\left(B\right)\right)=200$
Total number of people$\left(n\left(A\cup B\right)\right)=400$
Number of people those speak both languages,$n\left(A\cap B\right)=n\left(A\right)+n\left(B\right)-n\left(A\cup B\right)=200+250-400=50$