You are asked todetermine the concentration of a bacterial culture. You take 1.0 mLof the culture and add it to 4.0 mL of water (Tube #1). You thentake 1.0 mL from Tube #1 and add it to 14 mL of water (Tube #2).Finally, you take 1.0 mL from Tube #2 and add it to 19 mL of water(Tube #3). You then spread 0.20 mL from Tube #3 onto a nutrientagar plate and incubate the plate at 37°C. After 24 hours, youcount 215 colonies on the plate.

A. By what factor has the original culture beendiluted in Tube #1? 
B. By what factor has the ORIGINAL culturebeen diluted in Tube #2?
C. By what factor has the ORIGINAL culturebeen diluted in Tube #3?
D. What is the concentration of the original bacterial culture?