Let the largest one be X, then the ages of these five people are X, X-A, X-B, X-C and X-6, and the formula X+(X-A)+(X-B)+(X-C)+(X-6)=85*5.

X=85+(6+A+B+C)/5

Three of them are younger than X, bigger than X-6, and one is bigger than the other, so 1 is less than or equal to A.

2 is less than or equal to and better than B.

3 is less than or equal to c

6 is less than or equal to (a+b+c)

Because people's age is limited to an integer, (6+A+B+C) must be divisible by 5, and 12 is less than or equal to (6+A+B+C).