A culture of a certain bacteria doubles every hour. At 9:00am, there were already 120 bacteria. Which equation represents the number of bacteria, n, at 8:00 am? How many bacteria were there?

Question

2n=120 at 8:00am, there were 240 bacteria, 2n=120, at 8:00am, there were 60 bacteria, n/2=120 at 8:00am, there were 60 bacteria, n/2 = 120 at 8:00am, there were 240 bacteria

Answer 1

To find out how many bacteria were present at 8:00 am when the number of bacteria doubles every hour, we can work backwards from the amount at 9:00 am.

At 9:00 am, there were 120 bacteria. One hour earlier, at 8:00 am, the number of bacteria would have been half of that amount because the culture doubles every hour.

So, we can represent the number of bacteria at 8:00 am with the following equation:

\[ n = \frac{120}{2} \]

Calculating this gives:

\[ n = 60 \]

Therefore, at 8:00 am, there were 60 bacteria.

The correct equation that represents the number of bacteria, \( n \), at 8:00 am is:

\[ n = \frac{120}{2} \]

Resulting in:

At 8:00 am, there were 60 bacteria.