The average of 15 numbers is 72. The average of the first 6 numbers is 65. The average of the next 5 numbers is 20% higher than the average of the first 6. The 12th number is 8 less than the 15th, and the 13th is 5 greater than the 15th and if 14th number is 78. What is the average of the 12th and 13th numbers?