An overnight stock culture of 25 ml Bacillus megaterium is used as a sample. Two ml of this culture is added to a bottle containing 48 ml of buffer. This dilution is mixed well as all dilutions are!, and 5 ml of this is mixed in 15 ml of buffer. This second dilution is diluted by three successive 1/20 dilutions. The last (fifth) dilution is plated, i.e. 0.3 ml is plated on nutrient agar. After incubating the plate, 70 colonies are counted. 1. What was the final ditution in the second tube? 2. What was the final dilution in the 4th tube? 3. How many colony-forming units of E. coli culture were present in the original stock culture