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A culture of Staphylococcus is diluted as follows: (1) 50mL are added to 50mL of water....

A culture of Staphylococcus is diluted as follows:
(1) 50mL are added to 50mL of water.
(2) 100uL from (1) are then added to 9.9mL of water.
(3) 10uL from (2) are then added to 9.99mL of water.
(4) 10uL from (3) are plated for a pour plate and incubated.

There were 35 colonies counted on one quarter of the plate following incubation.

a) What was the overall dilution?
b) How many cfu/mL were present in the original culture?

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