Please help!

[SiO3]

Hi! I'm stuck with this problem. I need to solve it without using logs.
A particular colony of bacteria is being grown in a petri dish, and is expected to double
every hour and a half. A biologist predicts the colony will eventually cover the petri dish.
How many minutes will elapse between the time when the petri dish is half full and when it
is completely full?

Thanks a lot!!!

 

[Deleted member 4993]

Hi! I'm stuck with this problem. I need to solve it without using logs.
A particular colony of bacteria is being grown in a petri dish, and is expected to double
every hour and a half. A biologist predicts the colony will eventually cover the petri dish.
How many minutes will elapse between the time when the petri dish is half full and when it
is completely full?

Thanks a lot!!!

Just think about it a bit!

An hour and a half before the petri dish was full what was the size of the colony? ......... edited

You should not even need pencil and paper to solve it - let alone "log"!!

 

[Steven G]

Just think about it a bit!

An hour before the petri dish was full what was the size of the colony?

You should not even need pencil and paper to solve it - let alone "log"!!

Sir, you meant to say An hour and a half before the petri dish was full what was the size of the colony?

 

[mmm4444bot]

Hint: If we could run time backwards, we would see the bacterial volume decrease by one-half (not double), every 90 minutes.