Sheridan Company recently performed repair services for a customer that totaled $350. Somehow the bill was lost and the company accountant was trying to recreate the bill from memory. This is what was remembered: Total bill $700 Labor profit margin $10 Materials profit margin 20% Total labor charges $380 Cost of materials used $110 Total hourly cost $22.50 How many hours were billed on the job?

a. 19.1

b. 11.7

c. 16.9

d. 18.1