Hatelak, a sales representative for a manufacturing equipment company, has decided to spend less time traveling. He is going to spend only 172 hours per month with his customers. To do this he will have to give up some of his clients. The following information is from his last full month's sales activities. Large Medium Small Customers Customers Customers Number of customers 20 160 Average sale per customer $6,000 $2,000 $1,200 Commission (% of sales $) 10% 7% 5% Average time per customer 6 hours 4 hours 3 hours 1001 Required: a. What should be his customer mix in order to maximize his sales commissions? (3 marks) b. What will be his income at the best possible customer mix? (3 marks) c. What will be his income if he works an additional hour per month given that he made the best possible customer mix? (4 marks)