4.1 The daily production and cost data of a small manufacturer of smartphone cases are: MARGINAL VALUE OF INPUT OUTPUT PRODUCT MARGINAL PRODUCT (hours/day) (cases/day) (cases/hour) ($/hour) 0 10 10 20 40 30 90 40 130 50 160 60 180 70 190 80 190 The price of a case is $10. MPL, VMPL (cases or $/hour) 50 45 40 35 30 25 20 15 10 0 10 20 30 40 50 60 70 labor (hours/day) (a) In the range from 30 to 40 hours of labor per day, what are the marginal product (Aq/ AL) and value of marginal product of labor