Answer:
13, 14, 15, 16
Explanation:
Call the first number n. Then the next three consecutive numbers (assuming integers) are n + 1, n + 2, n + 3.
The mean is the total of the numbers divided by how many there are.
Simplify and multiply by 4.
The first number is 13.
The median is 14.5, halfway between the "middle" numbers 14 and 15. This is just a check; no additional equation is necessary.