Answer:
0.4
Explanation:
This is conditional probability.
Given that a student chosen at random has a sibling, we focus on the "sibling" column, and note that the sum of the entries is 0.75. (That indicates that 3/4 of the students surveyed have a sibling.)
The fraction pertaining to having a pet as well as a sibling is 0.3.
Thus, the probability that a student chosen at random has a pet as well as a sibling is 0.3/0.75, or 0.4.