Colony count help

[Gamewizard]

Hi,

 

So i have made some serial dilutions and counted my colonies from two plates (replicate plate also) taken the average and that is 30. These plates were from my 10^2 dilution. Overall i had made 7 dilutions from 10^8 to 10^1, and total dilution is 1 in 10. The vol i plated on to the agar plates was 1ml.

So to get CFU per ml in in the original stock solution (10^8), I need to use this formula which is Colony count per plate x dilution factor /vol plated. However, when it says dilution factor do they mean the total dilution factor which is 1 in 10? or the dilution of the actual plate which is 10^2 ?

 

Can someone please just clarify this, I have looked endlessly on the internet and no where does it say

 

Thank you