You can't get the elite four's phone numbers.
add them together and divide them by 4
The Answer is 26
Respectively, they are 3, 7, 5 and 7 but those four numbers do not have a common prime factor.
Forty and four respectively
The answer is X-13 + Y- 52 = Sum 65
You would add the two numbers in the middle and divide them by two and the answer would be the median.
The numbers are 51, 53, 55 and 57.