A plumber charges $93 for a job which takes 2 hours and $141 for 4 hours of work. Let $C be the plumbing cost for t hours of work. What is the linear rule connecting C and t?

A plumber charges $93 for a job which takes 2 hours and $141 for 4 hours of work. Let $C be the plumbing cost for t hours of work. What is the linear rule connecting C and t?

Use the model C = at + b where b is a fixed cost and a is the hourly rate.