Answer: 2.35 x 10^6 cfu/ml
Explanation:
Concentration of the original culture: ?
Dilution factor: 10^4
Colony count per plate: 47cfu
Volume of cultured plate: 0.2ml
Concentration of the original culture= Colony count per plate x Dilution factor
Volume of cultured plate
Concentration of the original culture = 47 x 10^4
0.2
Concentration of the original culture = 2.35 x 10^6 cfu/ml
You can further take the log of your answer which would be:
Log(2.35 x 10^6) = 6.371