Final answer:
Amanda rented the bike for approximately 8.51 hours.
Step-by-step explanation:
To determine how many hours Amanda rented the bike, we can subtract the cost of the helmet ($12) from the total amount paid ($39.63). This leaves us with $27.63. Since Amanda pays $3.25 per hour, we can divide $27.63 by $3.25 to find the number of hours. This gives us approximately 8.51 hours. Therefore, Amanda rented the bike for about 8.51 hours.
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