In a survey of 29 instructors, it was found that 22 liked whiteboards, 11 liked blackboards, and 7
Liked both. How many instructors did not like whiteboards?
A)14
B)7
C)3
D)4

Question

Quizplus · Accepted Answer

We know that 22 instructors liked whiteboards and 7 instructors liked both whiteboards and blackboards. Therefore, the number of instructors who liked only whiteboards is 22-7=15. Since there were a total of 29 instructors surveyed, the remaining instructors who did not like whiteboards can be found by subtracting the total number of instructors who liked whiteboards (including those who liked both) from 29: 29-(22+7)=29-29=0. Therefore, the number of instructors who did not like whiteboards is 0, making choice B the best answer. We know that 22 instructors liked whiteboards and 7 liked both whiteboards and blackboards. This means that 22-7=15 instructors only liked whiteboards. Therefore, the number of instructors who did not like whiteboards is 29-15=14. Choice B (7) is incorrect because that is the number of instructors who liked blackboards, not the number who did not like whiteboards. Choices C (3) and D (4) are also incorrect because they do not correspond to any logical calculation based on the information given.

In a Survey of 29 Instructors, It Was Found That