A culture of a certain bacteria doubles every hour. At 9:00 am there’s we’re already 120 bacteria. Which equation represents the number of bacteria, n, at 8:00 am! How many bacteria were there?
A: n/2 = 120; at 8:00, there were 240 bacteria.
B: 2n = 120; at 8:00 am, there were 60 bacteria.
C: n/2 = 120; at 8:00 am, there were 60 bacteria.
D: 2n = 120; at 8:00 am, there were 240 bacteria.
The correct equation is C: n/2 = 120.
To find the number of bacteria at 8:00 am, we need to go back in time by 1 hour. Since the culture doubles every hour, we need to divide the number of bacteria at 9:00 am (which is 120) by 2 to find the number at 8:00 am. Thus, the number of bacteria at 8:00 am is 120/2 = 60.
Therefore, the correct answer is: at 8:00 am, there were 60 bacteria.
The correct equation that represents the number of bacteria, n, at 8:00 am is option C: n/2 = 120. This equation is correct because the culture doubles every hour and goes back in time by one hour from 9 am to 8 am.
To calculate the number of bacteria at 8:00 am, we need to solve the equation:
n/2 = 120
By multiplying both sides of the equation by 2, we get:
n = 240
Therefore, at 8:00 am, there were 240 bacteria.
So, the correct answer is option C: n/2 = 120; at 8:00 am, there were 60 bacteria.
To solve this problem, let's work backward to find the number of bacteria at 8:00 am.
Knowing that the bacteria double every hour, we can determine the number of bacteria at 9:00 am by dividing the number of bacteria at 8:00 am by 2.
Let n represent the number of bacteria at 8:00 am.
So, the equation representing the number of bacteria, n, at 9:00 am would be:
n * 2 = 120
To find the number of bacteria at 8:00 am, we can divide 120 by 2, since the bacteria double every hour.
n = 120 / 2
n = 60
Therefore, at 8:00 am, there were 60 bacteria.
Looking at the given answer choices:
A: n/2 = 120; at 8:00 am, there were 240 bacteria. (Incorrect, the equation is incorrect and the number of bacteria is incorrect)
B: 2n = 120; at 8:00 am, there were 60 bacteria. (Correct)
C: n/2 = 120; at 8:00 am, there were 60 bacteria. (Incorrect, the equation is incorrect)
D: 2n = 120; at 8:00 am, there were 240 bacteria. (Incorrect, the equation is incorrect and the number of bacteria is incorrect)
The correct answer is B: 2n = 120; at 8:00 am, there were 60 bacteria.