Algebra

We can define variables to solve this problem. 

Let's let the common ratio of this geometric sequence be r.

We have

$16r = 1/4 \\ r = (1/4) / 16 = 1/64$

So the common ratio is 1/64. 

Now, we calculate for the 30th term. We have'

$(1/4) r^6 = (1/4)(1/64)^6\\ = (1/4) ( 1/4^3) ^6 \\ =(1/ 4)^19\\ =0.000000000003638$

So our final answer is 0.000000000003638.

Thanks! :)