Question

A random sample of students was surveyed and asked to list their grade level and whether or not they have a pet.
18 seventh graders said they have pets.
22 eighth graders said they don't have a pet.
40 eighth graders were surveyed.
35 total students said they don't have a pet.

Fill in the missing values in the table below.

Pets Survey
Pets No Pets Total
7th grade
8th grade
Total

Answer 1

To fill in the missing values in the table, let's analyze the given information step by step:

1. **7th Graders**:
- We know that 18 seventh graders have pets.

2. **8th Graders**:
- We know that 22 eighth graders do not have pets.
- We also know that a total of 40 eighth graders were surveyed.

Therefore, the number of eighth graders who have pets can be calculated as follows:
\[
\text{Eighth Graders with Pets} = \text{Total Eighth Graders} - \text{Eighth Graders without Pets}
\]
\[
\text{Eighth Graders with Pets} = 40 - 22 = 18
\]

3. **Total Students without Pets**:
- We know that a total of 35 students (from both grades) said they do not have a pet.
- We have already established that 22 eighth graders do not have a pet. Therefore we can find out how many seventh graders do not have a pet:
\[
\text{Seventh Graders without Pets} = \text{Total Students without Pets} - \text{Eighth Graders without Pets}
\]
\[
\text{Seventh Graders without Pets} = 35 - 22 = 13
\]

4. **Total for Each Grade**:
- Now we can find the total number of seventh graders surveyed:
\[
\text{Total Seventh Graders} = \text{Seventh Graders with Pets} + \text{Seventh Graders without Pets}
\]
\[
\text{Total Seventh Graders} = 18 + 13 = 31
\]
- The total number of eighth graders is already given as 40.

5. **Total Summary**:
- Now we can put together the categories for each row and the total:

### Pets Survey Table
```
Pets | No Pets | Total
---------------------------------
7th grade | 18 | 13 | 31
8th grade | 18 | 22 | 40
---------------------------------
Total | 36 | 35 | 71
```

### Filled Table
- **7th grade**: 18 with pets, 13 without pets, total 31.
- **8th grade**: 18 with pets, 22 without pets, total 40.
- **Total**: 36 with pets, 35 without pets, total 71.

This completes the filling of the table.