There are two ways to solve this problem. First, you can use the derived formula for geometric sequence which can be used to find any nth term of the sequence. Or, we can use the second easier way. Since we are given with the 700th term, and the asked is the 699th term, then that means,
(699th term)*(Common Ratio) = 700th term
699th term = 700th term/Common Ratio = 20/0.25 = 80