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)
Responses
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.
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.
2n=120; at 8:00 a.m., there were 240 bacteria.
2 n equals 120 ; at 8:00 a.m., there were 240 bacteria.
2n=120; at 8:00 a.m., there were 60 bacteria.
2 n equals 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.
The correct equation that represents the number of bacteria, n, at 8:00 a.m is "Start Fraction n over 2 End Fraction equals 120". Therefore, at 8:00 a.m., there were 60 bacteria.
To solve this problem, we can use the concept of exponential growth.
We know that the culture of bacteria doubles every hour. This means that if we start with n bacteria at a certain time, we will have 2n bacteria one hour later.
Given that at 9:00 a.m., there were already 120 bacteria, this means that at 10:00 a.m., there would be 2 * 120 = 240 bacteria.
To find out how many bacteria there were at 8:00 a.m., we need to work backwards. Since the bacteria double every hour, going back one hour means dividing by 2.
So, the equation that represents the number of bacteria at 8:00 a.m. is n / 2 = 120.
To find the value of n, we can multiply both sides of the equation by 2:
n = 2 * 120 = 240.
Therefore, at 8:00 a.m., there were 240 bacteria.
Therefore, the correct option is: n/2 = 120; at 8:00 a.m., there were 240 bacteria.