5.5 is the answer for the problem
Answer: 504
Step-by-step explanation:
When we select r things from n things in a order , we use permutations.
Formula for permutation: 
Given : The number of family members who are potential kidney donors. = 9
Number of people needed to be selected for best match, a second-best match, and a third-best match ( in an order)=3
Then, the number of possible orders are = 

Hence, the number of possible orders 504.
Answer:
Roberto is correct because 15/16 x 4/5 = 3/4.
Roberto's solution to the division problem is correct, but
there are no true statements on your list of choices.
300,563 Hope it helps! ^^
~Ash~