To solve the problem of finding the total number of bacteria in 100 milliliters of water when there are about 1,500,000 bacteria in 1 milliliter, we can follow these steps:
1. Given data:
- Number of bacteria per milliliter = 1,500,000 bacteria
- Volume of water = 100 milliliters
2. To find the total number of bacteria in 100 milliliters of water, multiply the number of bacteria per milliliter by the total volume of water (in milliliters):
[tex]\[
\text{Total number of bacteria} = (\text{Number of bacteria per milliliter}) \times (\text{Volume of water in milliliters})
\][/tex]
3. Substitute the given values:
[tex]\[
\text{Total number of bacteria} = 1,500,000 \times 100
\][/tex]
4. Perform the multiplication:
[tex]\[
1,500,000 \times 100 = 150,000,000
\][/tex]
5. Thus, the total number of bacteria in 100 milliliters of water is 150,000,000.
In scientific notation, 150,000,000 can be written as [tex]\(1.5 \times 10^8\)[/tex].
Hence, the correct answer is:
E. [tex]\(1.5 \times 10^8\)[/tex]