Urgent specific charge help

Hi,

I've tried to work out the specific charge of this multiple choice question and apparently got it wrong:

A calcium ion is formed by removing two electrons from an atom of Ca (20 protons, 20 neutrons). What is the specific charge?

I did (2*1.60*10^-19)/(40*1.67*10^-27) and got a specific charge of 4.8*10^6 C kg^-1 however it should have been 3.2*10^-19 C kg^-1.

Any help would be much appreciated! Thanks.

Hey maybe you misread the question. Your specific charge is correct. You will get 3.2*10^-19 if you multiply 2*1.6*10^-19.