Counter question. How to calculate how many tries it would take to reach a specific probability for an outcome? For example, how many times do I have to roll th

Counter question. How to calculate how many tries it would take to reach a specific probability for an outcome? For example, how many times do I have to roll the dice to have 90% chance of death? Due to my field of work, I'd solve everything by bruteforce, but I wonder what a more elegant solution could be.