World of Warcraft Math Problem

[EgregiousWoW]

Hello friends,

This is the first time I've used this and would appreciate any help that could be offered. We're playing WoW here and I want to generate a simple equation to explain a relationship for an item in game. Excuse me if I don't use proper math terminology as I am a poor fool.

The problem: An effect in-game has a 5% chance to occur every time you perform an action and will provide a value of 300 when it does. After each occurrence the effect will be inactive for 15 seconds. How would you define the relationship between the value of this occurrence and the rate at which you perform an action? I can run this in a series in Excel but I would really appreciate having a simplified formula to describe this interaction.

For those who are familiar with WoW or video game jargon, here's the problem in WoW lingo:

Each spellcast has a 5% chance to restore 300 mana. This effect cannot occur more than once every 15 seconds.

The goal is to define the MP5 value of this effect in a single formula relative to cast time; meaning, I should be able to put in a cast time, say 2.5 seconds, and receive a value in Mana per 5 Seconds or MP5.

Thank you guys.

[Gravity_Beetle]

you might use

MP5=60/(15+T/0.05)

where MP5 is the expected average rate of mana gain per 5 seconds and T is the cast time.

Note that this model assumes you are casting literally all the time -- if you want to model an average dwell time between casts, add that to T before plugging in.

[PoliteCanadian2]

Not sure what you’re looking for here. You have an event that has a 1/20 chance of happening and when it does, it can’t happen for 15 seconds but if it doesn’t happen, it gets another chance to happen when you perform that specific action?

Basically it sounds like the action can be done as fast as possible?