5 and 15 are the first two terms in a geometric sequence

5 and 15 are the first two terms in a geometric sequence. What is the arithmetic difference between the 9th term and the 7th term?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #86551