The sum of three consecutive natural numbers each divisible by 3 is 72. What is the largest among them ?

Let us take three consecutive numbers which are divisible by 3 are, 3x, 3x + 3 and 3x + 6.
3x + (3x + 3) + (3x + 6) = 72
9x + 9 = 72
9x = 63
i.e. x = 7
so, the numbers are 21, 24 and 27