IN THE INFINITE ARITHMETIC SEQUENCE 1, 11, 1.2,... WHAT TERM OF THE SEQUENCE IS 3?

Answer 1

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
...