Answer
$t=38 s$
Work Step by Step
We know that;
$V=\frac{KQ}{R}$
This can be rearranged as:
$Q=\frac{RV}{K}$
We plug in the known values to obtain:
$Q=\frac{0.01\times 1000}{9\times 10^9}=1.1111\times 10^{-9}C$
Now,
$N=2\times \frac{(1.1111\times 10^{-9})}{(1.6\times 10^{-19})}=1.3889\times 10^{10}decays$
Thus,
$t=\frac{1.3889\times 10^{10}}{3.70\times 10^8}=38 s$
