3. State whether each sequence is arithmetic or geometric, and then find the explicit and recursive formulas for each sequence. (10 points: 5 points each) Formulas:

Part I: The total value of a collection of nickels can be described by this sequence:
5, 10, 15, 20, 25, 30, ...
Type of sequence:

Explicit formula:

Recursive formula:

Part II: The number of rats living in an abandoned building increases each year. The total number of rats can be described by this sequence:
2, 6, 18, 54, 162, ...
Type of sequence:

Explicit formula:

Recursive formula: