Question

a survey of 240 households.91 had a dog. 70 had a cat. 31 had a cat and dog. 91 had neither a cat or a dog and did not have a parakeet. 7 had a cat, a dog and a parakeet. how many had a parakeet only?

Answer 1

A total of 240 households participated in the survey.

91 of then had neither a cat, a dor or a parakeet.

Then, 159 of them had at least one animal.

7 of then had a cat, a dog and a parakeet.

Then, 152 of them had one or two animals between a cat, a dog and a parakeet.

31 of them had a cat and a dog.

Then, 121 of then had a dog only, a cat only, a dog and a parakeet, a cat and a parakeet or a parakeet only. Between these, we want to find the ones who had a parakeet only. Only 91 - 31 = 60 of these 121 households must had at least a dog and only 70 - 31 = 39 of these had at least a cat.

Therefore, the number of households that had a parakeet only is 121 - 60 - 39 = 22