Spoorthii
Can somebody help with the first question? How is it 11 out of 20?
Sure!
1. We are asked to
find the probability that "if one teacher is selected at random from those surveyed, that he or she holds a second job, rents out one or more rooms in his or her home, or both".
2. Probability is
much easier to understand as sets and we're picking a random person from the all sets together. There are three sets (holds a second job, rents out one or more rooms, or both) and the total probability is the union of the 3.
3. Let's visualize our initial Venn diagram.

4. The first set is the people who hold a second job.

5. The second set is the people who rent out one or more rooms.

6. The third set is the people who do/have both.

7. The union of all 3 sets is just the third set. The probability to pick someone in that area is \(= \frac{people \ in \ red}{all \ people} = \frac{5 + 3 + 3}{5 + 3 + 3 + 9} = \frac{11}{20}\).
8. So, the answer should be \(\frac{11}{20}\).
I hope that helped you!
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