Question

The average of thirteen number is 80. The average of the first five numbers is 74.5 and that of the next five numbers is 82.5. The 11th number is 6 more than the 12th number and the 12th number is 6 less than the 13th number. What is the average of the 11th and the 13th numbers?

• A. 87.5
• B. 86
• C. 87
• D. 86.5

Answer 1

Answer: (C)