Question

The count in a bacteria culture was 900 after 15 minutes and 1100 after 35 minutes. Assuming the count grows exponentially,

What was the initial size of the culture?

Answer 1

300

Explanation:

1100 = 900
`e^(k*20)`

1.222222 =
`e^(k*20)`

ln(1.222) = 20k ln(e)

k = ln(1.222)/20

k = .2004

900 = x
`e^(15* .20004)`

900/x =
`e^(15* .20004)`

`e^(15*.2004) = 900/x`

x = 900/
`e^(15*.2004)`

x = 300