What is the 5th term of this geometric sequence? 100, 20, 4, 0.8, …a.124.8b.0.2c.0.16d.0.032?

Hello : 
the common ratio is m 20/100=0.8/4=1/5 = 0.2= r
the nth term is :  An =A1 × r^(n-1)
if n=5  the 5th term is : A5 = 100×(0.2)^(5-1) = 100×0.16 =16

22.