One ml of E.coli is mixed
with 1ml of dye. A drop of this dilution is placed on a Petroff-Hausser counting
chamber. Five large, double-lined squares, each containing a volume of 1/1,250,0000
cc, are counted giving the following results: 61, 74, 78, 63 and 64 bacteria.
How many bacteria are there per cc in the original sample?