To find the number of bacteria at 8:00 a.m., we need to consider that the bacteria doubles every hour.
If we denote the number of bacteria at 8:00 a.m. as \( n \), then by 9:00 a.m. (which is one hour later), the number of bacteria would be \( 2n \).
Given that there are 120 bacteria at 9:00 a.m., we can set up the following equation:
\[ 2n = 120 \]
To find \( n \), we solve for \( n \):
\[ n = \frac{120}{2} = 60 \]
Thus, the equation that represents the number of bacteria at 8:00 a.m. is \( 2n = 120 \), and at 8:00 a.m., there were 60 bacteria.
So the correct response is:
2n = 120; at 8:00 a.m., there were 60 bacteria.
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