The equation you need to use is [tex]Q=IT[/tex] where Q is the charge in C, I is the current in Amps and T is the time in seconds.
So we have T = 60s
I = [tex]50 \times 10^-^6[/tex]A
let's work out Q
[tex]Q=IT = (50\times 10^{-6}) \times 60 = 3 \times 10^-^3 [/tex]C
this is the total charge passing a point in a minute so divide by the charge of one electron ([tex]1.6 \times 10^{-19}[/tex]) to find the number of electrons passing the point in a minute which equals [tex]1.875 \times 10^{16}[/tex]
