The easiest way to solve this problem is to determine what factor
expands the ratio of 3 : 2 : 1 to the three vases of 12 flowers each.
Therefore we say 3X + 2X + 1X = 36. Adding, we get 6X = 36.
Dividing by 6 we get X = 6. Now we can see that if all vases started
with 12 flowers and if we simply move 6 from one vase to one other we obtain
the ratio we’re looking for. E is the correct answer.