I'm not sure how the answer to part A is 21 either, if you could explain that would be appreciated. Thank you in advance!

You are in charge of a project at the local community center. The center needs to remodel one of the rooms in time for the start of a new program. Delays in the project mean that the center must rent other space at a nearby church at additional cost. Time and cost data for your project are contained in the table below. Your interest is in minimizing the cost of the project to the community center. Activity Normal Cost ($) Crash Cost ($) Immediate Predecessor(s) START A B Normal Time (days) 0 8 6 4 6 5 4 4 Crash Time (days) 0 5 4 1 4 5 3 1 0 50 40 70 20 30 80 50 60 0 D E F G 0 410 180 460 80 30 190 350 START START B AC A, C B D 6 4 100 H FINISH E, F G H 0 0 0 a. Using the normal times for each activity, what is the earliest date you can complete the project? The corresponding project duration using the normal times is 21 days. (Enter your response as an integer.) b. Suppose the variable overhead costs are $50 per day for your project. Also, suppose that the center must pay $60 per day for a temporary room on day 17 or beyond. Find the minimum-cost project schedule. Fill in the table below to show the proper schedule time for each activity after crashing) for completing the project at minimum cost. (Enter your responses as integers.) Activity Time (days) Activity Time (days) A E B F G D H