Talk:Valentine 2018 Event (US)/@comment-130.204.138.233-20180125102248/@comment-221.133.13.116-20180125112756

Each quartz roll you have 1% chance for a 5 star Servant, or 99% chance of not 5 star Servant. So with 100 quartz rolls, you'll have 0.99^100, about 36.6% of no 5 star Servant at all. The guaranteed of 10-rolls is only about 4 star, so it has no effect on 5 star Servant chance. In your case, 80 quartz rolls and you had about 44.65% chance of no 5 star Servant. It's not as unlikely as you thought. Also, even if you get that 1%, there's still chance that you'll get someone not on the rate up banner...