If ${10}^{9 }$ electrons move out of a body to another body every second, then the time required to get a total charge of $1 C$ on the other body is 

The charge given out in one second

$= 1.6 x {10}^{-19}C x {10}^9 = 1.6 x {10}^{-10} C$

Time required to accumulate a charge of $1 C$

$=\frac{1}{1.6\times {10}^{-10}}=6.25\times {10}^{9}s=198$years