# SPM Practice 2 (Geometric Progression) : Question 13

Question 13 (Hard question, try it!]

The sum of the first n term of a geometry progression is given by $6\left(1-{0.5}^{n}\right)$ , Find
(a) The fourth term of the progression,
(b) The sum to infinity of the progression.

[Note : ${T}_{n}={S}_{n}-{S}_{n-1}$ ]