Q.

In a survey it is to be found that 70% of employees like bananas and 64% like apples. If x% like both bananas and apples, then

1 x≥34  
2 x≤64  
3 34≤x≤64  
4 All of these  

Ans.

(3)

Let A and B denote the set of employees who like bananas and apples respectively and total number of employees be 100.

∴  n(A)=70,  n(B)=64,  n(U)=100  and  n(A∩B)=x

Now, n(A∪B)≤100

∴  n(A)+n(B)-n(A∩B)≤100

⇒  70+64-x≤100⇒x≥34                  ...(i)

Also, A∩B⊆B

∴  n(A∩B)≤n(B)⇒x≤64                      ...(ii)

By (i) and (ii), we have 34≤x≤64