For each job, a plumbing services company charges a one-time service fee of $50 and a $125 per hour rate for labor. let n be the total amount the company charges in dollars, for a job that takes b hours to complete. write an equation that represents the relationship between n and b

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)