Alyssa, Angel, and Gustavo are planting flowers in the courtyard outside their condo building. All three of them will get to enjoy the flowers once they are planted, but they must agree on how many to plant. The cost function for flowers is given by c(f)=0.3125*f^3 , where f is the number of flowers. What is the marginal cost of providing flowers? the total valuation per flower by the three condo residents is $60. What is the optimal number of flowers for the condo residents to plant