Using the relation between velocity, distance and time, it is found that her average speed for the final 30 miles is of 55.56 mph.
Velocity is distance divided by time, that is:
[tex]v = \frac{d}{t}[/tex]
Simone travels 90 miles at an average speed of 40 mph, hence the time is given by:
[tex]t_1 = \frac{90}{40} = 2.25[/tex]
She then travels a further 30 miles, with an average speed for the journey of 43 mph. Hence, she traveled 90 + 30 = 120 miles, and the total time is given by:
[tex]t = \frac{120}{43} = 2.79[/tex]
Hence, in the second part, she traveled 30 miles in 2.79 - 2.25 = 0.54 hours, so the velocity is given by:
[tex]v = \frac{d}{t} = \frac{30}{0.54} = 55.56[/tex]
Her average speed for the final 30 miles is of 55.56 mph.
More can be learned about the relation between velocity, distance and time at https://brainly.com/question/24316569
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