How is the definition of average violated? By plugging in numbers for c, d, e and f, I can understand why c < A, d < A, e < A, f < A would not work because suppose c=1, d=2, e=3, f=4. If we took the average of these numbers, we get A = 2.5. So, c=1 is less than A=2.5, and d=2 is less than A =...