Answer: 2
Step-by-step explanation:
Let Set A represents the number of employees cooked food.
Set B represents the number of employees washed dishes.
Set C represents the number of employees operated the cash register .
Given : n(A)=9 ; n(B)=14 ; n(C)=22
n(A∩B)=4 ; n(A∩C) = 2 ; n(B∩C)=7 ; n(A∩B∩C)=1
Using the given information, we have made a Venn diagram below.
Using Venn diagram , we have
n(only A)= n(A)-(n(A∩B)+n(A∩C)+n(A∩B∩C))
⇒n(only A)=9-(4+2+1)=9-7=2
Hence, 2 employees only cooked food.