a.) Karen is a trusted employee whose productivity declines as she works more and more hours each day. After careful observation of her work performance, her manager prepared the following chart. Daily Number of Hours Worked by Karen / Total Numbers of Work Units Completed 1/100 2/190 3/270 4/340 5/400 6/450 7/480 8/500 Karen's total cost to the firm is $11 per hour. Each work unit completed is worth $0.21 to the firm. Ignoring all other possibilities and considerations, for how many hours should the firm hire Karen per day?

b.) The NASDAQ system lists MassBank Company currently trading at bid price $15.30 and offer price $15.90. How much commission a dealer will receive if 100 shares are traded?

c.) The bid price of Boston Beer Company common stock is $12.15 and the offer price is $12.42. How much would an investor receive from selling 100 shares of Boston Beer Company common stock directly to the dealer?

d.) The bid price of Staple common stock is $18.40 and offer price is $18.80. How much will an investor have to pay to buy 100 shares of Staple common stock directly from dealer? $______