Question

5 multiple choice 1 point if a participant is selected at random from this group, what is the probability that they have at least one pet? 21/34 20/34 33/34 1/34 9/12

Explanation:

Step1: Recall probability formula

Probability = $\frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}$. Let the total number of participants be $n = 34$ (assumed from the denominators in options).

Step2: Use complementary - probability

The probability of having at least one pet is $P(X\geq1)$. The complement of having at least one pet is having no pets. Let the number of participants with no pets be $n_0$. If we assume the total number of participants $n = 34$, and assume the number of participants with no pets is $1$ (so that we can find the probability of having at least one pet). Then $P(X\geq1)=1 - P(X = 0)$. If $P(X = 0)=\frac{1}{34}$, then $P(X\geq1)=1-\frac{1}{34}=\frac{34 - 1}{34}=\frac{33}{34}$.

Answer:

C. 33/34