edutorrescasana wrote:
Considering "mean of four integers will not change if all the integers are multiplied by any constant", shouldnt all the numbers be 0 and then the sum of the largest and smallest be 0?
All numbers being zero is a valid set, but not the only valid set. The question asks "What is
always true..."
Possible sets of 4 integers whose mean does not change if all a integers are multiple by any constant:
0, 0 ,0 0
-2, -1, -2, 2
-3, 0, 1, 2
The largest and smallest integers in the last example do not equal zero.
There are not positive and negative integers in the first set.
All have a mean of 0.