Originally Posted by

**Tangera** Hello! I am quite confused about the formula needed for geometric progression, and would appreciate it if someone could explain how to solve geometric progression questions using the example question below...thank you!!

A geometric series has first term a and common ration r, where |r| < 1. The sum to infinity of the series is 8. The sum to infinity of the series is obtained by adding all the odd-numbered terms (i.e. 1st term + 3rd term + 5th term + ...) is 6. Find the value of r.