The current is defined as the amount of charge transferred through a certain point in a certain time interval:
[tex]I= \frac{Q}{\Delta t} [/tex]
where
I is the current
Q is the charge
[tex]\Delta t[/tex] is the time interval
For the lightning bolt in our problem, Q=6.0 C and [tex]\Delta t= 2.0 \cdot 10^{-3}s[/tex], so the average current during the event is
[tex]I= \frac{Q}{\Delta t} = \frac{6.0 C}{2.0 \cdot 10^{-3} s}=3000 A [/tex]
