How do I find the frequency or percentage chance for two independent timed events to happen simultaneously? If I have two events that occur on a specific interval (one every 8 seconds, the other every 200 milliseconds) but were not started synchronously, how can I calculate the frequency with which these two events will occur at the same time? Looking at the numbers, it seems that unless they start synchronously, they will _never_ coincide. If they started synchronously, in a perfect world, it would be every 8 seconds. Obviously there is some variation/imperfection because they _do_ coincide occasionally despite not starting at the same time. I suppose I am looking for a harmonic, or additive function. Forgive me, my math knowledge is lacking.

If the intervals are rational multiples, you can calculate the least common multiple. That will give you the interval between recurrences, assuming there is one at all. There will be one if the time for one delays from the other by a multiple of the greatest common divisor. For example, if one event recurs every 60 seconds and the other recurs every 33 seconds, the least common multiple is 660 seconds. The matches, if any, will recur that frequently. There will be a match if the delay from the first to the second is a multiple of the greatest common divisor, which is 3 seconds. If the delay is not a multiple of this, they will never match.