Nested IF functions

Hi all

New member here and am hoping someone can help me a nested if function, or a better function for my problem.

I have a drug that is taken with a 16 day half life, therefore total life of the drug is 32 days. If 400mg taken on day one, 12.5mg will be released daily for the next 32 days. Then 400mg taken on day 3 another 12.5mg will be released from that date and so on.

For this I have a used a simple if function of =if(C2="x",D2/32,0) with this data set.



The problem I have is that at the end of the 32 days, I need to trend the values down, so the 12.5mg of the 400mg dose from day 1 will be deducted from the concentration column after 32 days/count, and then the 12.5mg from the 400mg day 3 dose will be deducted from the concentration after 32 count from day 3 and so on.

Idea is for the blood concentrations of the different doses will be added together over the next 32 days, but after the 32 days will then stop being as the life of the drug is up.

I'm sure a count function of some sort needs to be used in a nested if formula, but can't come up with something that works.

Would appreciate any help

Thanks

Ryan