Answer :

Certainly! Let's solve the problem step-by-step to find the average speed of the truck driver.

Problem:
A truck driver traveled 275 miles in 5 hours. What was his average speed in miles per hour?

Solution:

1. Identify the given values:
- Distance traveled: 275 miles
- Time taken: 5 hours

2. Use the formula for average speed:
[tex]\[ \text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}} \][/tex]

3. Substitute the given values into the formula:
[tex]\[ \text{Average Speed} = \frac{275 \text{ miles}}{5 \text{ hours}} \][/tex]

4. Calculate the result:
[tex]\[ \text{Average Speed} = 55 \text{ miles per hour} \][/tex]

Therefore, the average speed of the truck driver is [tex]\(55\)[/tex] miles per hour.

Answer:
The correct option is:
D. 55