Option: C is the correct answer.
C. 5
<h2>Step-by-step explanation:</h2>We will solve the following problem with the help of the Venn diagram.
Based on the Venn diagram we are asked to find the value of v i.e. those who have parakeet only.
From the information that:
- 35 had a dog we have:
x+y+10=35
i.e.
x+y=25
Also, based on the information :
- 28 had a cat we have:
u+z+10=28
i.e.
u+z=18
Also, 42 had neither a cat nor a dog nor a parakeet.
This means it cover the outer region of the three circles.
Total 100 families were surveyed it means that:
42+x+y+10+u+z+v=100
i.e. 42+25+10+18+v=100
i.e. 95+v=100
i.e. v=100-95
i.e. v=5
Hence, the number of families who have only parakeet are: 5
