[b]Regarding #2, that is not how probability works[/b]. [b]Your probability of receiving a gjallarhorn after 4 engram decodes with a 1/4 (25%) drop rate is a 68.38% chance. [/b] I will now explain why. A common misconception is that you are guaranteed that item when you decode an engram x number of times, where 1/X is the drop rate. (In your scenario, 1/4 ~ 25%) Your mathematical probability actually never changes, you are never guaranteed anything. The probability that your engram will drop the item at least once in x decodes is 1 minus the probability that it will not drop that item in x decodes, or 1 - (1 - y)^x where x= number of decodes, and y= drop rate. Thus, in your gjallarhorn example of a 25% (1/4) drop rate on engrams, the actual probability of receiving a gjallarhorn after 4 engram decodes is represented by this equation: 1 - (1 - (1/4))^4 1 - (3/4)^4 And your actual probability of receiving a gjallarhorn after 4 engram decodes is [b]68.38% chance.[/b] [i](Similarly you can solve how many attempts would be necessary to earn a 90% favor with the equation 1 - (1-y)^x > .9)[/i]