The average of eleven numbers is 54. The average of the first four numbers is 48 and that of the next four numbers is 25% more than the average of the first four. The ninth number is 8 greater than the 11thnumber and the tenth number is 4 greater than the 11th number. What is the average of the 9th and the 10thnumbers?

• A. 54
• B. 56
• C. 52.6
• D. 54.4