Question

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

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

Answer 1

Let n be the number at 8:00 a.m. Since the culture doubles in one hour, 2n = 120. Solving gives n = 60.

So the correct equation is 2n = 120, and there were 60 bacteria at 8:00 a.m.