Answer:
There will be 200 000 bacteria after 8 hours
Step-by-step explanation:
The crop quadruples every hour.
x represents the number of hours that pass after preparing the crop
y represents the number of bacteria after x hours.
The equation for y in function of x 3 hours after observing the crop is:
[tex]y = 192(4^{x - 3})[/tex]
We want to know after how long there will be 200 000 bacteria.
Then we make y = 200 000 and clear x.
[tex]200\ 000 = 192(4^{x - 3})\\\\log(200\ 000) = log(192(4^{x-3}))\\\\log(200\ 000) = log(192) + log(4 ^{x-3})\\\\log(200\ 000) - log(192) = (x-3)log(4)\\\\\frac{log(200\ 000) - log(192)}{log(4)} = (x-3)\\\\x = 3 + \frac{log(200\ 000) - log(192)}{log(4)}\\\\x = 8\ hours[/tex]