The logistic curve has applications in many fields

The logistic curve has applications in many fields. In medicine, for example, it can represent the amount of a medication that is in the bloodstream for a short period of time just after ingestion while the drug is filtered into the bloodstream.  A person ingests 200 milligrams (mg) of a medication. After 30 minutes, there are 100 mg of the medication in the bloodstream. After 60 minutes, there are 180 mg of medication in the bloodstream.  Using the spreadsheet,  assign appropriate values to L and C and then adjust B until you are able to match the given infomation.

Part A:   L =

Part B:  C=

Part C:   B= 

Part D: The amount of medication in the bloodstream after 20 minutes is approximately how many mg?