Answer:
0.078125.
Step-by-step explanation:
This is a geometric sequence with first term a1 = 20 and common ratio r = 10/20 = 5/10 = 0.5.
nth term = a1 r^(n -1) so here:
9th term = 20(0.5)^(9-1)
= 20(0.5)^8
= 0.078125.
