Question

Kara did a survey to determine to study the types of pets that students in her school had. She surveyed 300 students and found that 40% of them had cats, 12% had both cats and dogs, and 45%
didn't have either. How many of the students that Kara surveyed had dogs?
1) 61
2) 71
3) 81
4) 91​

Answer 1

Answer:

(C)81

Step-by-step explanation:

Total Number of Students =300

Percentage who had cats, n(C) = 40%

Percentage who had both cats and dogs , $n(C \cap D)$ = 12%

Percentage who had neither cats nor dogs, $n(C \cup D)'$ =45%

Now:

Universal Set, $U = n(C)+n(D)-n(C \cap D)+n(C \cup D)'$

$100 = 40 + n(D)-12+45\\n(D)=100-73\\ Percentage of those who own dogs =27\%$

Therefore:

Number of Students who had dogs

=27% of 300

=81