Formula for Avg from 2 columns (last 10 cells) - A newbie User!!

Hello Everyone

I need some help to develop a formula to find avg of last 10 days and last 5 days
I m total new to this formula developing thingy.

Solve this.PNG

this is the case, I know its simple for u guys..

I just want the cell to show avg per tap
like for 10 days we need to add last 10 cells of product column and divide it by sum of last 10 cells in taps used column
thats it i tried but in vain.. i dont know why..

Also i want it be blank for present and future dates. (not compulsory)

thanks in advance