A certain bacteria doubles its population every 15 mins. Home many bacteria will u end up with if u leave 10 bacteria to multiply for 3 hrs?

Number of 15-minute-period in 3 hours = (3 × 60 / 15) = 12

Number of bacteria after 3 hours = 10 × 2¹² = 40960

A = 10*2^(12) = 40,960

10*2^(12) = 40,960

10 × 2¹² = 40960

I wish I could receive compounded bank interest at that rate!

Given the rate of bacteria doubling, why is the claim of a certain bleach to kill 99% of germs at all imprsssive, when the 1% will soon multiply?

P(t) = P(0) e^(kt)
when t=15
P(t)= 2P(0)

2P(0) = P(0) e^(15k)
e^(15k) = 2
15k = ln(2)
k = ln(2)/15
k = 0.0462098

P(t) = P(0) e^(0.0462098t)
P(0) = 10
P(t) = 10 e^(0.0462098t)
let t= 180 (minutes)

P(t) = 10 e^((0.0462098)(180))
= 40959.9
= 40,960

A certain bacteria doubles its population every 15 minutes.
How many bacteria will you end up with
if you leave 10 bacteria to multiply for 3 hours?
There are twelve 15 minutes in 3 hours.
10 × 2^12 = 40,960

Dipanshu has given you the answer, 10*2^(12) = 40,960
But here is how you would work that out for yourself.

Doubled, means gets multiplied by 2
Think about "doubles population every 15 mins"
In 15 mins the 10 bacteria become 10 * 2
In another 15 mins the 10 bacteria become 10 * 2 * 2
See this as after 30 mins the 10 bacteria become 10 * 2^(30/15)
Then after 45 mins the 10 bacteria become 10 * 2^(45/15) = 10 * 2^3

Observe that the 3 came from 45/15, so hopefully you can now see that
after t minutes the power would be t/15 so we can write the formula as:-
after t minutes 10 bacteria become 10 * 2^(t/15)

That allows us to find the number of bacteria at any particular time t in minutes
Three hours is 180 minutes which is 12 lots of 15 minutes
The number of bacteria after 3 hours is given by
10 * 2^(180/15) = 10*2^(12) = 40,960

I want to say approximately 240 cells(or whatever unit you're using) of bacteria will be present after 3 hours. I'm not quite sure though...