Fair enough.
Here what I did:
Took e=f/q and e=v/d (F is electric force, q is charge, e is energy in field, v is volts, and d is distance, but Im sure you guys know these formulas)
Got f/q=v/d
Got fd/v=q
Then plugged it in and got 5.4*10^-9, if memory serves.
Problem is the group I was in didn't get consistent answers, and this makes me want to check my answer, but my teacher wouldn't help me, so I came to you guys to see if you had the same procedure, or at least a proceduce that resulted in the same answer.
Hope that helps, and thanks in advance to any answers I get.