alrighhhht worked it out on my own :)
I figured, why log to find the rate, 20th root it.
125000/100000=r^20
(20th root) 1.25=r
r=1.01
200000=100000(1.01)^t
2=1.01^t
log 2/log1.01=t
t=62 minutes which is the answer in the back of my textbook. Thanks for setting me on the right path Char.Limit :D
Well i can get this far but i can't get farther sorry.
125000=100000(rate)^20
125000/100000=r^20
log (125000/100000)=20log r
I don't know how to go farther, if r had a value and i was solving for time i would have no problem with this.
So would my rate be 2? if so then would this be right 120000=100000(2)^t
1.25=2^t
log1.25/log2=t?
What confuses me is when it says doubling period, is that time or the rate?
Homework Statement
A culture begins with 100,000 bacteria and grows to 125,000 bacteria after 20 min. What is the doubling period to the nearest minute?
Homework Equations
Current=Original(rate)^time
The Attempt at a Solution
I can get make the first part out...