Do you mean subtract two each day? If so...
4x3=12 and 12 divided by 2 is 6 so it would take six days to reach zero
or
you could manually subtract two from 6 each days as in 12-2=10 (1 day), 10-2=8 (2 days), and so on...
Answer:

And replacing we got:

And then the final term would be:

Step-by-step explanation:
For this case we have the following expression:

And we can use the binomial theorem given by:

And for this case we want to find the fourth term and using the formula we have:

And replacing we got:

And then the final term would be:

Step-by-step explanation:
5/8=20/p
p=32
.............