To find the speed at which Amelia needs to travel in order to reach her destination in the desired time, we can start with the formula for distance:
\[ d = vt \]
Where:
- \( d \) is the distance (388 miles),
- \( v \) is the speed (which we want to find),
- \( t \) is the time (7 hours).
To isolate \( v \), we can rearrange the formula:
- Divide both sides by \( t \):
\[ v = \frac{d}{t} \]
Now we have the formula that highlights the quantity of interest (speed):
\[ v = \frac{d}{t} \]
Substituting in the values for \( d \) and \( t \):
\[ v = \frac{388 \text{ miles}}{7 \text{ hours}} \]
Now, let's calculate that:
\[ v \approx 55.43 \text{ miles per hour} \]
Thus, Amelia would need to travel at approximately 55.43 miles per hour to reach Mesa in about 7 hours.