I have a test coming up and i know what some question will be on. One question is about the time it takes to discharge a capacitor from "full" to a given point or percent of initial charge. How would i go about doing this.

I know the it has to do with the time constant RC and the equation of discharging a capacitor i just don’t know how i would find the time it takes.

**3. The attempt at a solution**

http://ift.tt/1kJnkPK