Final answer:
The average lifespan of a dollar bill, according to the Federal Reserve, is around 5.8 years.
Step-by-step explanation:
The average lifespan of a dollar bill, according to the Federal Reserve, is around 5.8 years. However, the lifespan can vary depending on factors such as usage and condition. Dollar bills are constantly being circulated and replaced to ensure they remain in good condition for use.