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 240 bacteria.
2 n equals 120 ; at 8:00 a.m., there were 240 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 60 bacteria.

Answer 1

To find the number of bacteria at 8:00 a.m. when the bacteria double every hour, we need to divide the number of bacteria at 9:00 a.m. by 2.

At 9:00 a.m. there are 120 bacteria. Therefore, the equation representing the number of bacteria at 8:00 a.m. is:

\[ n \cdot 2 = 120 \]

This means that at 8:00 a.m.:

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

Thus, the correct response is:

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