Answer:
The probability that the pet seen was sick is 53.57%.
Step-by-step explanation:
The probability of an event <em>E</em> is the ration of the number of favorable outcomes to the total number of outcomes.

Here,
n (E) = number of favorable outcomes
N = total number of outcomes
Denote the events as follows:
<em>C</em> = the pet is a cat
<em>D</em> = the pet is a dog
<em>O </em>=<em> </em>the pet is some other animal
<em>S</em> = the pet is sick.
The data provided is summarized as follows:
n (C) = 28
n (C ∩ S) = 3
n (D) = 42
n (B ∩ S) = 4
n (O) = 24
n (O ∩ S) = 8
Compute the probability that a cat was sick as follows:

Compute the probability that a dog was sick as follows:

Compute the probability that another animal was sick as follows:

Compute the probability that the pet seen was sick as follows:
P (S) = P (C ∩ S) + P (D ∩ S) + P (O ∩ S)

Thus, the probability that the pet seen was sick is 53.57%.