To find out how far Caleb travels, you can use the formula:
\[ \text{Distance} = \text{Speed} \times \text{Time} \]
Given that Caleb drives at a speed of 15 miles per hour for 3 hours, you can calculate the distance as follows:
\[ \text{Distance} = 15 , \text{miles per hour} \times 3 , \text{hours} = 45 , \text{miles} \]
Caleb travels 45 miles.
The unit rate, which in this case is the speed at which Caleb is traveling, is 15 miles per hour.