25$ is the flat fee. 50$ is the amount charged per hour. Therefore the equation is C=25+50h where c is the total cost and h is the amount of hours.
C=25+50h
To find the amount of money for 8 hours simply plug in 8 for h and you get 400. Don't forget to add the flat fee of 25. The total cost for 8 hours of service is 425.
To find the amount of money for 10 hours of work, plug in 10 for h and you get 500. Add 25 to 500 and you get 525 for a total of 10 hours of work.