Chapter 6 - Exponential Functions and Sequences - 6.6 - Geometric Sequences - Exercises - Page 336: 15

The sequence is geometric.

Prepare a table. The sequence is $2,10,50,250,...$ Calculate ratio between each pair of consecutive terms. $\frac{10}{2}=5$ $\frac{50}{10}=5$ $\frac{250}{50}=5$ The common ratio is $5$. So, the sequence is geometric.