Finding mass only given electrons

[CathyLynn45]

Homework Statement

A neutral balloon picks up 42 electrons when it is rubbed on someone's head.
Calculate how much the mass of the balloon has increased.

Homework Equations

E=F/q
F=kq1q2/r^2

The Attempt at a Solution

Well, I do know the answer is 3.82 x 10^-29.
Using E=F/q q=1.6x10^-19 but I don't know where the electric field comes from.
Using F=kq1q2/r^2 both q's= 1.6x10^-19 and k=9x10^9 but I don't know where the distance comes from.
I feel like I haven't been given enough information...? Please help.

 

[Doc Al]

What's the mass of an electron? (Look it up!)

 

[phyzguy]

I think you are over-complicating this. How much do 42 electrons weigh?

 

[CathyLynn45]

Yeah, never mind I just got it