A poll was taken of 100 students at a commuter campus to find out how they got to campus. The results are below. How many are not using any of the three?
32 said they drove alone.
34 rode in a carpool.
31 rode public transportation.
7 used both carpools and public transportation.
8 used both a carpool and sometimes their own cars.
9 used buses as well as their own cars.
5 used all three methods.
To find out how many students are not using any of the three methods (driving alone, carpooling, and using public transportation), we need to subtract the total number of students who use any of the three methods from the total number of students surveyed.
Let's calculate it step by step:
1. Start with the total number of students surveyed: 100.
2. Calculate the number of students who use at least one of the three methods:
- 32 drove alone.
- 34 rode in a carpool.
- 31 rode public transportation.
- 7 used both carpool and public transportation.
- 8 used both a carpool and sometimes their own cars.
- 9 used buses as well as their own cars.
- 5 used all three methods.
To calculate the total, we need to add up the students who used each method but make sure not to double count those who used multiple methods.
32 + 34 + 31 - 7 - 8 - 9 + 5 = 78.
3. Finally, subtract the total number of students who use any of the three methods from the total number of students surveyed:
100 - 78 = 22.
Therefore, there are 22 students who do not use any of the three methods.