The average age of the couple was 25, giving a total initial age sum of 50 years. When the twins were born, the average age of the four family members became 14, setting their total age at that time to 56 years; since the parents aged by two years each, the parents' total age was 54, meaning the combined age of the twins was 2 years. When the third child was born, the total age of the five family members was 13.6 times 5, equaling 68 years; subtracting the parents' new age sum of 58 years and the third child's age of 0 leaves 10 years for the twins. Using the method of averages, the twins are currently 5 years old each because the family's current total age of 93.6 years minus the third child's current age of 3.6 years leaves 90 years for the parents and the twins, and 90 minus the parents' 80 years equals 10 years for both twins.