microbiology dilution homework - please help!! need answer by 3/6/08?

[Chris]

due to poor planning, you run out of sterile water in the midst of serial dilutions. You make the dilutions from the original 100 ml culture flask into four 10 ml tubes with each respectively receiving 1 ml, 1ml, 3 ml, and 2 ml. The last dilution yields 180 colonies on a plate (spread). What was the original concentration of bacteria in the flask culture. Explain what could have you done differently with the limited amount of water to make four serial 10-fold dilutions. Also, a dosage of 0.6 g has been ordered. The strength available is 1 g in 2.0 ml. Determine the volume which will contain the dosage ordered.