A manufacturer of disk controllers subjects each new controllers to rigorous testing. Of newly assembled controllers, 84% pass the test with no rework. Controller that fail the initial test are reworked once; 75% of these machines pass a second test. Those controller that fail the second test are reworked the second time and retested; 90% of them pass and the test are scrapped. Define Y to be the number of rework cycles for a randomly chosen controller. What is the variance of Y?