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

Question

, at 8:00 a.m? How many bacteria were there?(1 point)
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.

n/2=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.

n/2=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.

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

Answer 1

To find the number of bacteria at 8:00 a.m., we need to consider that the bacteria double every hour.

At 9:00 a.m. there are 120 bacteria. Therefore, 1 hour earlier, at 8:00 a.m., there must have been half that amount.

To express this mathematically, if $n$ represents the number of bacteria at 8:00 a.m., we can write the equation:

$$2n=120$$

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

$$n=\frac{120}{2}=60$$

The correct representation is:

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