A culture of a certain bacteria doubles every hour. At 9:00 a.m, there were already 120 bacteria. Which equation represents the number of bacteria, n , at 8:00 a.m? How many bacteria were there?(1 point)

Question

Responses

2n=120; at 8:00 a.m., there were 60 bacteria.
2 n equals 120 ; at 8:00 a.m., there were 60 bacteria.

n2=120; at 8:00 a.m., there were 240 bacteria.
Start Fraction n over 2 End Fraction equals 120 ; at 8:00 a.m., there were 240 bacteria.

n2=120; at 8:00 a.m., there were 60 bacteria.
Start Fraction n over 2 End Fraction equals 120 ; at 8:00 a.m., there were 60 bacteria.

2n=120; at 8:00 a.m., there were 240 bacteria.

Answer 1

To determine how many bacteria were present at 8:00 a.m., we recognize that the number of bacteria doubles every hour. Given that there were 120 bacteria at 9:00 a.m., we can find the number of bacteria at 8:00 a.m. by dividing by 2 (since they doubled between 8:00 a.m. and 9:00 a.m.).

So, at 8:00 a.m., the number of bacteria \( n \) can be calculated as follows:

\[ n = \frac{120}{2} = 60 \]

Now, the equation that represents the number of bacteria at 8:00 a.m. is:

\[ 2n = 120 \]

Thus, the answer is:

2n=120; at 8:00 a.m., there were 60 bacteria.