Question

which is not like the others 21 15 6 16 27

Answer 1

The number that is not like the others is 16. All of the other numbers are divisible by 3. (21/3 = 7, 15/3 = 5, 6/3 = 2, 27/3 = 9)

Answer 2

That would be 16 because all the other number are divisible by 3 and not 16