11. Lonely Guy Repair Service recently performed repair services for a customer that totalled Sh 400. Somehow the bill was lost, and the company accountant was trying to recreate the bill from memory. This is what was remembered: Total bill Sh 600 Labor profit margin Sh 10 Materials profit margin 20% Total labor charges Sh 390 Cost of materials used Sh 120 Total hourly cost Sh 22.50 What was the material loading charge? a. 37.5% b. 43.8% c. 61.3% d. 75%