IN THE INFINITE ARITHMETIC SEQUENCE 1, 11, 1.2,... WHAT TERM OF THE SEQUENCE IS 3?
I assume you meant
1,1.1,1.2,...
Tn = 0.9 + 0.1n
So, to find which term is 3,
0.9 + 0.1n = 3
0.1n = 2.1
n = 21
So, T21 = 3
Makes sense. Every 10 terms another 1.0 is added:
T1 = 1
T11 = 2
T21 = 3
T31 = 4
...