The closest distance between Earth and Mars is approximately 3.39×10^7 miles. The fastest rocket leaving Earth travels at an average speed of approximately 3.6×10^4 miles per hour.

Using these values, we can calculate the time it would take for the fastest rocket leaving Earth to reach Mars.

First, we divide the distance between Earth and Mars by the speed of the rocket:
Time = Distance / Speed
Time = 3.39×10^7 miles / 3.6×10^4 miles per hour
Time = 9.42×10^2 hours

Therefore, it would take approximately 942 hours for the fastest rocket leaving Earth to reach Mars.

At that rate, which expression could be used to determine the approximate number of hours it would take the rocket to travel from Earth to Mars?

To determine the approximate number of hours it would take for the rocket to travel from Earth to Mars, you can use the expression:

\( \frac{3.39 \times 10^7}{3.6 \times 10^4} \)