Question

Среди 80 опрошенных учащихся у 38 живёт дома собака,у 35 кошка,а у 14 нет ни кошки ни собаки.Сколько человек содержат дома и кошку и собаку.

Answer 1

80-14=66(люди у которых есть животные ),тогда
38+35=73(есть животные),
73-66=7
Ответ: 7

Answer 2

Analysis

According to the given information, there were 80 students surveyed. Out of these students: - 38 students have a dog at home. - 35 students have a cat at home. - 14 students do not have either a cat or a dog.

We need to determine how many students have both a cat and a dog at home.

Solution

To find the number of students who have both a cat and a dog at home, we can use the principle of inclusion-exclusion.

We start by adding the number of students who have a dog and the number of students who have a cat: 38 (students with a dog) + 35 (students with a cat) = 73.

However, by doing this, we have counted the students who have both a cat and a dog twice. So, we need to subtract the number of students who have both a cat and a dog.

According to the given information, 14 students do not have either a cat or a dog. Therefore, the number of students who have both a cat and a dog can be calculated as follows:

73 (students with a dog or a cat) - 14 (students with neither a cat nor a dog) = 59.

Therefore, there are 59 students who have both a cat and a dog at home.

Answer

There are 59 students who have both a cat and a dog at home.