A student investigated the effect of two antibiotics on the growth of the bacterium Vibrio cholerae.
During the investigation, the student:
After 24 hours, they diluted the contents of each bottle by 1 in 5 000 0005\,000\,0005000000 (2×10−72 \times 10^{-7}2×10−7). They then transferred 0.3 cm30.3\text{ cm}^30.3 cm3 samples from the first bottle onto each of 3 separate agar plates. They repeated this with 0.3 cm30.3\text{ cm}^30.3 cm3 samples from the second bottle and the third bottle, resulting in 9 agar plates in total.
They incubated the plates for 48 hours.
Table 1 shows the number of colonies of bacteria counted on each plate after 48 hours:
| Plate | Number of colonies with streptomycin | Number of colonies with kanamycin | Number of colonies with no antibiotic |
|---|---|---|---|
| 1 | 178 | 24 | 412 |
| 2 | 184 | 28 | 418 |
| 3 | 193 | 26 | 415 |
Calculate the mean number of bacteria in the undiluted bottle of liquid culture containing streptomycin. Give your answer in standard form.
Starting with a single bacterium, calculate how many generations it would take to produce at least the number of bacteria you calculated in part 1 (assume no bacteria die).
