Simple ratio problem that I can't solve.?

Question

One fifth of criminals are hard-core criminals. The hard-core criminals commit two-thirds of the criminal acts. What is the ratio of the number of criminal acts committed by the average hard-core criminal to the number commited by the average criminal who is not hard-core? P.S. I hope this sort of question isn't frowned upon since its very low level math (ACT test practice). If so let me know.

Answer 1

Since hard-core criminals commit 2/3 of the criminal acts, average criminals commit the other 1/3, so the ratio is 2:1.