4,5
The numbers are 9, 10 and 11 with a sum of 30.
The numbers are 4 and 5: 4 + 5 = 9
The sum of such numbers is 504.
The answer is, obviously, 9.
9 and 11
8, 9 and 10.
7, 9 & 11.
The numbers are 5, 7 and 9.
The numbers are -5 and -4.
Answer is 4000000: The sum of the first N odd numbers is N^2. Look at 1,3,5 for example. There are 3 numbers and the sum is 9 which is 3^2. Add 7 and the sum is 16 which is 4^2. So the of the first 2000 consecutive odd numbers is 2000^2 Note 2000 is 2(10^3). When we square that it is 4x10^6=4000000
average is 9 so 8, 9 & 10
The numbers are 9, 11 and 13.