Easy Question, then the Pain Begins..

Anyone that can answer these two problems for me I will gladly name my first born after you.

The first question is relatively easy:

For a bet with a 33% chance of success (2/1) such as choosing the correct number to appear on a 3 sided die, if I was given odds of 21/10 for this bet what size bankroll would I need to ensure a 95% degree of certainty that I would not go broke.

The second question:

If the EV for a given bet is known (like in the above 2/1 vs. 21/10 example)what other variables need to be known to determine the bankroll to ensure a 95% degree of certainty that you would not go broke.

How does this formula to determine the bankroll change when there is a range of bets each with differnt EV's?


Hopefully this is enough information, if you need any clarication or questions answered, please post or PM me.

Thankyou in advance.