The ratio of the present age of A and B is 6: 7. The Ratio of A's age 10 years hence and B's age 5 years ago is 4: 3. If the average age of A, B and C is 31. Age of C, 2 years hence and present age of D are in the ratio 6: 5. Find the sum of the ages of A, B, C and D 4 years hence.