Final answer:
Teresa's driving rate is 72 miles per hour, calculated from her initial journey. With this rate, it would take her 12 hours to drive 864 miles.
Step-by-step explanation:
To solve this problem, we first need to find the rate at which Teresa was driving. We can calculate her driving rate by dividing the distance she traveled by the time it took.
Rate = Distance ÷ Time
Rate = 576 miles ÷ 8 hours
Rate = 72 miles per hour
Now, we use this rate to find out how long it would take Teresa to drive 864 miles.
Time = Distance ÷ Rate
Time = 864 miles ÷ 72 miles per hour
Time = 12 hours
Therefore, it would take Teresa 12 hours to drive 864 miles.