Batteries

How do you propose to solve this? Same rules as before: We will help, but we want you to try it first.

ok
I just need help with the equation set up. If I have an equation, I can take it from there.

Of course. It's just a matter of plugging values into the equation. Converting a real world situation into an equation is THE problem.

This is a theory question. You don't need an equation here, just an understanding of what it means to have a "normal" distribution. Do an internet search on the words "normal distribution standard deviation" and you should get enough information to understand this question. The question is how much of a normal distribution do you expect to be one standard deviation above the mean.